Anti-mesothelin binding proteins

ABSTRACT

The present disclosure provides compositions and methods relating to antigen binding proteins, in particular, antibodies and bispecific antibodies which specifically bind to mesothelin. The disclosure provides nucleic acids encoding such antigen binding proteins and antibodies and methods of making and using such antibodies, including methods of treating and preventing cancer or other hypoproliferative disorders and related disorders by administering such antigen binding proteins and antibodies to a subject in need of such treatment.

This application is a Continuation of U.S. application Ser. No. 15/141,463, filed Apr. 28, 2016, which was a Continuation of U.S. application Ser. No. 13/926,847, filed Jun. 25, 2013, which claims benefit of U.S. Provisional Patent Application Nos. 61/789,678, filed Mar. 15, 2013, and 61/665,139, Jun. 27, 2012, each of which is incorporated herein by reference in its entirety.

REFERENCE TO THE SEQUENCE LISTING

The present application is being filed along with a Sequence Listing in electronic format. The Sequence Listing is provided as a file entitled A-1719-US—NP_SL.txt created Jun. 25, 2013, which is 258 KB in size. The information in the electronic format of the Sequence Listing is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The field of this invention relates to compositions and methods related to anti-mesothelin binding proteins.

BACKGROUND OF THE INVENTION

Mesothelin is a glycoprotein present on the surface of cells of the mesothelial lining of the peritoneal, pleural and pericardial body cavities. Mesothelin (MSLN) was identified in 1992 with the mAb K1 that was generated by the immunization of mice with human ovarian carcinoma (OVCAR-3) cells (Chang, et al., Int J. Cancer. (1992) 50:373-81). It was purified from the human pancreatic cancer cell line HPC—Y5 and was shown to have megakaryocyte potentiating ability and hence named megakaryocyte potentiating factor (MPF) (Yamaguchi et al. (1994) J. Biol. Chem. 269:805-808). The mesothelin gene (MSLN) encodes a 71-kilodalton (kDa) precursor protein that is processed to a 40-kDa protein termed mesothelin, which is a glycosyl-phosphatidylinositol-anchored glycoprotein present on the cell surface (Chang, et al, Proc Natl Acad Sci USA (1996) 93:136-40). The mesothelin cDNA was cloned from a library prepared from the HPC—Y5 cell line (Kojima et al. (1995) J. Biol. Chem. 270:21984-21990). The cDNA also was cloned using the monoclonal antibody K1, which recognizes mesotheliomas (Chang and Pastan (1996) Proc. Natl. Acad. Sci. USA 93:136-40).

Mesothelin is a differentiation antigen whose expression in normal human tissues is limited to mesothelial cells lining the body cavity, such as the pleura, pericardium and peritoneum. Mesothelin is also highly expressed in several different human cancers, including mesotheliomas, pancreatic adenocarcinomas, ovarian cancers, stomach and lung adenocarcinomas. (Hassan, et al., Eur J Cancer (2008) 44:46-53) (Ordonez, Am J Surg Pathol (2003) 27:1418-28; Ho, et al., Clin Cancer Res (2007) 13:1571-5).

Mesothelin is also shed from tumor cells as a soluble form of the protein, as compared to the native membrane bound version (Hellstrom, et al, Cancer Epidemiol Biomarkers Prev (2006) 15:1014-20.; Ho, et al., Cancer Epidemiol Biomarkers Prev (2006) 15:1751). Structurally, mesothelin is expressed on the cell surface as a 60 kDa precursor polypeptide, which is proteolytically processed into a 31 kDa shed component (corresponding to MPF) and a 40 kDa membrane bound component (Hassan et al. (2004) Clin. Cancer. Res. 10:3937-3942). Shed serum mesothelin has been approved by the US Food and Drug Administration as a diagnostic biomarker in malignant mesothelioma.

The biological function of mesothelin is still not clear. Knockout mice have been prepared in which the mesothelin gene was disrupted by homologous recombination (Bera, T. K. and Pastan, I. (2000) Mol. Cell. Biol. 20:2902-2906). No anatomical, hematologic or reproductive abnormalities were detected, indicating that mesothelin function is not essential for growth or reproduction, at least in those mice.

Mesothelin does specifically interact with CA125 (also known as MUC-16), a mucin-like glycoprotein present on the surface of tumor cells that previously had been identified as an ovarian cancer antigen. Further, binding of CA125 to membrane-bound mesothelin mediates heterotypic cell adhesion and CA125 and mesothelin are co-expressed in advanced grade ovarian adenocarcinoma (Rump, A. et al. (2004) J. Biol. Chem. 279:9190-9198). Expression of mesothelin in the lining of the peritoneum correlates with the preferred site of metastasis formation of ovarian cancer and mesothelin-CA125 binding is thought to facilitate peritoneal metastasis of ovarian tumors (Gubbels, J. A. et al. (2006) Mol. Cancer. 5:50).

Mesothelin can also be used a marker for diagnosis and prognosis of certain types of cancer because trace amounts of mesothelin can be detected in the blood of some patients with mesothelin-positive cancers (Cristaudo et al., Clin. Cancer Res. 13:5076-5081, 2007). It has been reported that mesothelin may be released into serum through deletion at its carboxyl terminus or by proteolytic cleavage from its membrane bound form (Hassan et al., Clin. Cancer Res. 10:3937-3942, 2004). An increase in the soluble form of mesothelin was detectable several years before malignant mesotheliomas occurred among workers exposed to asbestos (Creaney and Robinson, Hematol. Oncol. Clin. North Am. 19:1025-1040, 2005). Furthermore, patients with ovarian, pancreatic, and lung cancers also have elevated soluble mesothelin in serum (Cristaudo et al., Clin. Cancer Res. 13:5076-5081, 2007; Hassan et al., Clin. Cancer Res. 12:447-453, 2006; Croso et al., Cancer Detect. Prev. 30:180-187, 2006). Accordingly, mesothelin is an appropriate target for methods of disease prevention or treatment and there is a need for effective antibodies specific for mesothelin.

SUMMARY OF THE INVENTION

In one embodiment, the invention provides an isolated anti-mesothelin human antibody or fragment thereof, wherein said antibody has at least one of the following properties: binds to a different epitope than the MORAb-009 antibody; competes for binding with Ab237; specifically binds to human, cyno, rat and murine mesothelin; does not internalize upon binding to mesothelin; when bound to mesothelin, does not inhibit CA125 interaction with mesothelin; has a binding affinity KD of at least 5.0 pM against human mesothelin; has enhanced effector function; binds to membrane-bound mesothelin preferentially over soluble mesothelin; reduces the growth of mesothelin expressing tumor cells in vivo.

In another embodiment, the invention provides a method of inhibiting or reducing the growth of mesothelin expressing tumor cells in an animal, comprising administering to said animal a therapeutically effective dose of the antibodies of the invention.

In a further embodiment, the invention provides a method of determining if a subject has mesothelin expressing tumor cells, comprising: contacting a tumor sample from the subject with an antibody of the invention; and detecting binding of the antibody to the sample, wherein an increase in binding of the antibody to the sample as compared to binding of the antibody to a control sample identifies the subject as having mesothelin expressing tumor cells.

In another embodiment, the invention provides an isolated antibody or antigen binding protein or fragment thereof, wherein the antibody or antigen binding protein or fragment thereof specifically binds to mesothelin and comprises 3 heavy chain CDRs and 3 light chain CDRs with sequences selected from the group consisting of: SEQ ID NOs: 45, 46, 47 of the heavy chain and SEQ ID NOs: 9, 10, 11 of the light chain; SEQ ID NOs: 48, 49, 50 of the heavy chain and SEQ ID NOs: 12, 13, 14 of the light chain; SEQ ID NOs: 51, 52, 53 of the heavy chain and SEQ ID NOs: 15, 16, 17 of the light chain; SEQ ID NOs: 51, 52, 53 of the heavy chain and SEQ ID NOs: 18, 19, 20 of the light chain; SEQ ID NOs: 54, 55, 56 of the heavy chain and SEQ ID NOs: 21, 22, 23 of the light chain; SEQ ID NOs: 57, 58, 59 of the heavy chain and SEQ ID NOs: 24, 25, 26 of the light chain; SEQ ID NOs: 60, 61, 62 of the heavy chain and SEQ ID NOs: 27, 28, 29 of the light chain; SEQ ID NOs: 63, 64, 65 of the heavy chain and SEQ ID NOs: 30, 31, 32 of the light chain; SEQ ID NOs: 63, 64, 65 of the heavy chain and SEQ ID NOs: 33, 34, 35 of the light chain; and SEQ ID NOs: 63, 64, 65 of the heavy chain and SEQ ID NOs: 36, 37, 38 of the light chain, wherein each of said CDRs are identical to or comprise 1, 2, or 3 amino acid residue substitutions relative to their specified sequence.

In another embodiment, the invention provides an isolated antibody or antigen binding protein or fragment thereof, wherein the antibody or antigen binding protein or fragment thereof specifically binds mesothelin and comprises a heavy chain variable domain and a light chain variable domain selected from the group consisting of: a heavy chain variable domain comprising SEQ ID NO: 86 and a light chain variable domain comprising SEQ ID NO: 72; a heavy chain variable domain comprising SEQ ID NO: 87 and a light chain variable domain comprising SEQ ID NO: 73; a heavy chain variable domain comprising SEQ ID NO: 88 and a light chain variable domain comprising SEQ ID NO: 74; a heavy chain variable domain comprising SEQ ID NO: 88 and a light chain variable domain comprising SEQ ID NO: 75; a heavy chain variable domain comprising SEQ ID NO: 89 and a light chain variable domain comprising SEQ ID NO: 76; a heavy chain variable domain comprising SEQ ID NO: 90 and a light chain variable domain comprising SEQ ID NO: 77; a heavy chain variable domain comprising SEQ ID NO: 91 and a light chain variable domain comprising SEQ ID NO: 78; a heavy chain variable domain comprising SEQ ID NO: 92 and a light chain variable domain comprising SEQ ID NO: 79; a heavy chain variable domain comprising SEQ ID NO: 92 and a light chain variable domain comprising SEQ ID NO: 80; a heavy chain variable domain comprising SEQ ID NO: 92 and a light chain variable domain comprising SEQ ID NO: 81; a heavy chain variable domain comprising SEQ ID NO: 93 and a light chain variable domain comprising SEQ ID NO: 82; a heavy chain variable domain comprising SEQ ID NO: 94 and a light chain variable domain comprising SEQ ID NO: 83, wherein each of said heavy chain variable domain and light chain variable domain have at least 90%, 95% or 100% identity relative to their specified sequence.

In a further embodiment, the invention provides an antibody or antigen binding protein or fragment thereof is a bispecific antibody and binds an additional target other than MSLN. In one embodment, the additional target is CD3. In a further embodiment, the CD3 is human and/or cynomolgus CD3. In yet a further embodiment, the CD3 is human and/or mouse and/or rat and/or cynomolgus CD3.

In another embodiment, the invention provides a bispecific single chain antibody, said bispecific single chain antibody comprising binding domains specific for CD3 and MSLN, wherein the corresponding variable heavy chain regions (V_(H)) and the corresponding variable light chain regions (V_(L)) regions are arranged, from N-terminus to C-terminus, in the order, V_(H)(MSLN)—V_(L)(MSLN)—V_(H)(CD3)-V_(L)(CD3), or V_(H)(CD3)-V_(L)(CD3)-V_(H)(MSLN)—V_(L)(MSLN), or V_(L)(MSLN)—V_(H)(MSLN)—V_(H)(CD3)-V_(L)(CD3), or V_(H)(CD3)-V_(L)(CD3)-V_(L)(MSLN)—V_(H)(MSLN), or V_(L)(MSLN)—V_(H)(MSLN)—V_(L)(CD3)-V_(H)(CD3), or V_(L)(CD3)-V_(H)(CD3)-V_(L)(MSLN)—V_(H)(MSLN), or V_(H)(MSLN)—V_(L)(MSLN)—V_(L)(CD3)-V_(H)(CD3), or V_(L)(CD3)-V_(H)(CD3)-V_(H)(MSLN)—V_(L)(MSLN).

In one embodiment, the invention provides a bispecific single chain antibody that comprises a first VH as set forth in SEQ ID NO: 86, a first VL as set forth in SEQ ID NO: 72, a second VH as set forth in SEQ ID NO: 118, and a second VL as set forth in SEQ ID NO: 120.

In another embodiment, the invention provides a bispecific single chain antibody that comprises: a first VH CDR1 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 45; a first VH CDR2 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 46; a first VH CDR3 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 47; a first VL CDR1 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 9; a first VL CDR2 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 10; and a first VL CDR3 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 11; a second VH CDR1 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 115; a second VH CDR2 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 116; a second VH CDR3 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 117; a second VL CDR1 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 112; a second VL CDR2 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 113; and a second VL CDR3 having an amino acid sequence identical to or comprising 1, 2, or 3 amino acid residue substitutions relative to SEQ ID NO: 114.

In another embodiment, the invention provides a bispecific single chain antibody having the sequence is set forth in SEQ ID NO: 127 or SEQ ID NO: 129. In another embodiment, the invention provides a bispecific single chain antibody comprising any of SEQ ID NOs: 158-185 and further comprising SEQ ID NO: 122.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 provides a summary of MSLN expression data from ovarian and pancreatic tumor and normal cells.

FIG. 2 provides images of MSLN expression from primary ovarian tumor samples.

FIG. 3 summarizes the estimated new cases and deaths attributed to cancers expressing MSLN, and the % incidence of MSLN expression.

FIG. 4 summarizes binding and biochemical characteristics of the anti-MSLN antibodies, including Kd and species (cynomolgus, rat, mouse) cross-reactivity.

FIGS. 5 and 6 summarize antibody binning data of the anti-MSLN antibodies.

FIGS. 7-9 summarize anti-MSLN antibody ADCC mediated cell killing data for several different tumor lines.

FIGS. 10-12 summarize anti-MSLN antibody CDC mediated cell killing data.

FIG. 13 provides a photographic summary of results of ADCP assays using anti-MSLN antibodies.

FIG. 14 summarizes anti-MSLN antibody ADCP mediated cell killing data.

FIGS. 15-17 summarize in vivo results of anti-tumor activity of the anti-MSLN antibodies.

FIG. 18 provides an alignment of several different scFv anti-MSLN molecules used in the generation of BiTE molecules.

FIG. 19 summarizes anti-MSLN antibody binning based on competitive binding assays and sequence comparisons.

FIGS. 20 and 21 summarize in vitro assays performed with several anti-MSLN/anti-CD3 BiTE molecules (different VH/VL orientations of the same BiTE) as compared to control, demonstrating binding to both human MSLN and human CD3 expressed on tumor cells; experiments were also performed that demonstrate binding to both cynomolgus MSLN and cynomolgus CD3 (data not shown).

FIG. 22 summarizes an in vitro T-cell activation assay performed with several anti-MSLN/anti-CD3 BiTE molecules as compared to control BiTE molecules, demonstrating T-cell activation by the anti-MSLN/anti-CD3 BiTE molecules.

FIGS. 23-24 summarize in vitro assays performed with several anti-MSLN/anti-CD3 BiTE molecules as compared to control BiTE molecules, demonstrating cytokine release when the anti-MSLN/anti-CD3 BiTE molecules are incubated with MSLN expressing tumor cells in the presence of unstimulated T-cells.

FIGS. 25 and 26 summarize in vitro cytotoxicity assays performed with several anti-MSLN/anti-CD3 BiTE molecules as compared to control BiTE molecules, demonstrating specific T-cell mediated lysis of MSLN-expressing ovarian tumor cells.

FIG. 27-29 summarize in vivo tumor growth inhibition assay using several different tumor types (gastric cancer cells, SK—OV-3, NCI—N87, OVCAR-8, A-2780) performed with an anti-MSLN/anti-CD3 BiTE molecule as compared to controls, demonstrating a dramatic reduction in tumor growth by the anti-MSLN/anti-CD3 BiTE molecule against MSLN expression tumor cells.

FIG. 30 summarizes the results of an in vivo pharmacokinetic assay using MSLN BiTE molecules, indicating the pharmacokinetics are consistent with inhibition of tumor growth.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to antigen binding proteins such as antibodies that specifically bind to mesothelin. In one embodiment, the mesothelin is human mesothelin. In another embodiment, the mesothelin is cynomologous mesothelin. In another embodiment, the mesothelin is murine mesothelin. In another embodiment, the mesothelin is rat mesothelin. In one embodiment, the antibodies of the invention specifically bind to human, cynomologous, murine and rat mesothelin, and as such, the term mesothelin as used herein refers to all of these species of mesothelin. The antigen binding proteins are useful for treating cancer and related diseases.

The present invention further provides compositions, kits, and methods relating to antigen binding proteins that specifically bind to mesothelin. Also provided are nucleic acid molecules, and derivatives and fragments thereof, comprising a sequence of polynucleotides that encode all or a portion of a polypeptide that binds to mesothelin, such as a nucleic acid encoding all or part of an anti-mesothelin antibody, antibody fragment, or antibody derivative. The present invention further provides vectors and plasmids comprising such nucleic acids, and cells or cell lines comprising such nucleic acids and/or vectors and plasmids. The provided methods include, for example, methods of making, identifying, or isolating antigen binding proteins that bind to human mesothelin, such as anti-mesothelin antibodies, methods of determining whether an antigen binding protein binds to mesothelin, methods of making compositions, such as pharmaceutical compositions, comprising an antigen binding protein that binds to human mesothelin, and methods for administering an antigen binding protein that binds mesothelin to a subject, for example, methods for treating cancer that comprises tumor cells that express mesothelin.

Definitions

Polynucleotide and polypeptide sequences are indicated using standard one- or three-letter abbreviations. Unless otherwise indicated, polypeptide sequences have their amino termini at the left and their carboxy termini at the right, and single-stranded nucleic acid sequences, and the top strand of double-stranded nucleic acid sequences, have their 5′ termini at the left and their 3′ termini at the right. A particular section of a polypeptide can be designated by amino acid residue number such as amino acids 1 to 50, or by the actual residue at that site such as asparagine to proline. A particular polypeptide or polynucleotide sequence also can be described by explaining how it differs from a reference sequence.

Unless otherwise defined herein, scientific and technical terms used in connection with the present invention shall have the meanings that are commonly understood by those of ordinary skill in the art. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. Generally, nomenclatures used in connection with, and techniques of, cell and tissue culture, molecular biology, immunology, microbiology, genetics and protein and nucleic acid chemistry and hybridization described herein are those well known and commonly used in the art. The methods and techniques of the present invention are generally performed according to conventional methods well known in the art and as described in various general and more specific references that are cited and discussed throughout the present specification unless otherwise indicated. See, e.g., Sambrook et al. Molecular Cloning: A Laboratory Manual, 2d ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989) and Ausubel et al., Current Protocols in Molecular Biology, Greene Publishing Associates (1992), and Harlow and Lane Antibodies: A Laboratory Manual Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1990), which are incorporated herein by reference. Enzymatic reactions and purification techniques are performed according to manufacturer's specifications, as commonly accomplished in the art or as described herein. The terminology used in connection with, and the laboratory procedures and techniques of, analytical chemistry, synthetic organic chemistry, and medicinal and pharmaceutical chemistry described herein are those well known and commonly used in the art. Standard techniques can be used for chemical syntheses, chemical analyses, pharmaceutical preparation, formulation, and delivery, and treatment of patients.

The following terms, unless otherwise indicated, shall be understood to have the following meanings: The term “isolated molecule” (where the molecule is, for example, a polypeptide, a polynucleotide, or an antibody) is a molecule that by virtue of its origin or source of derivation (1) is not associated with naturally associated components that accompany it in its native state, (2) is substantially free of other molecules from the same species (3) is expressed by a cell from a different species, or (4) does not occur in nature. Thus, a molecule that is chemically synthesized, or expressed in a cellular system different from the cell from which it naturally originates, will be “isolated” from its naturally associated components. A molecule also may be rendered substantially free of naturally associated components by isolation, using purification techniques well known in the art. Molecule purity or homogeneity may be assayed by a number of means well known in the art. For example, the purity of a polypeptide sample may be assayed using polyacrylamide gel electrophoresis and staining of the gel to visualize the polypeptide using techniques well known in the art. For certain purposes, higher resolution may be provided by using HPLC or other means well known in the art for purification.

The terms “peptide” “polypeptide” and “protein” each refers to a molecule comprising two or more amino acid residues joined to each other by peptide bonds. These terms encompass, e.g., native and artificial proteins, protein fragments and polypeptide analogs (such as muteins, variants, and fusion proteins) of a protein sequence as well as post-translationally, or otherwise covalently or non-covalently, modified proteins. A peptide, polypeptide, or protein may be monomeric or polymeric.

The term “polypeptide fragment” as used herein refers to a polypeptide that has an amino-terminal and/or carboxy-terminal deletion as compared to a corresponding full-length protein. Fragments can be, for example, at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 50, 70, 80, 90, 100, 150 or 200 amino acids in length. Fragments can also be, for example, at most 1,000, 750, 500, 250, 200, 175, 150, 125, 100, 90, 80, 70, 60, 50, 40, 30, 20, 15, 14, 13, 12, 11, or 10 amino acids in length. A fragment can further comprise, at either or both of its ends, one or more additional amino acids, for example, a sequence of amino acids from a different naturally-occurring protein (e.g., an Fc or leucine zipper domain) or an artificial amino acid sequence (e.g., an artificial linker sequence).

Polypeptides of the invention include polypeptides that have been modified in any way and for any reason, for example, to: (1) reduce susceptibility to proteolysis, (2) reduce susceptibility to oxidation, (3) alter binding affinity for forming protein complexes, (4) alter binding affinities, and (4) confer or modify other physicochemical or functional properties. Analogs include muteins of a polypeptide. For example, single or multiple amino acid substitutions (e.g., conservative amino acid substitutions) may be made in the naturally occurring sequence (e.g., in the portion of the polypeptide outside the domain(s) forming intermolecular contacts). A “conservative amino acid substitution” is one that does not substantially change the structural characteristics of the parent sequence (e.g., a replacement amino acid should not tend to break a helix that occurs in the parent sequence, or disrupt other types of secondary structure that characterize the parent sequence or are necessary for its functionality). Examples of art-recognized polypeptide secondary and tertiary structures are described in Proteins, Structures and Molecular Principles (Creighton, Ed., W. H. Freeman and Company, New York (1984)); Introduction to Protein Structure (C. Branden and J. Tooze, eds., Garland Publishing, New York, N.Y. (1991)); and Thornton et al. Nature 354:105 (1991), which are each incorporated herein by reference.

A “variant” of a polypeptide (e.g., an antibody) comprises an amino acid sequence wherein one or more amino acid residues are inserted into, deleted from and/or substituted into the amino acid sequence relative to another polypeptide sequence. Variants of the invention include fusion proteins.

A “derivative” of a polypeptide is a polypeptide (e.g., an antibody) that has been chemically modified, e.g., via conjugation to another chemical moiety such as, for example, polyethylene glycol, albumin (e.g., human serum albumin), phosphorylation, and glycosylation. Unless otherwise indicated, the term “antibody” includes, in addition to antibodies comprising two full-length heavy chains and two full-length light chains, derivatives, variants, fragments, and muteins thereof, examples of which are described below.

An “antigen binding protein” is a protein comprising a portion that binds to an antigen and, optionally, a scaffold or framework portion that allows the antigen binding portion to adopt a conformation that promotes binding of the antigen binding protein to the antigen. Examples of antigen binding proteins include antibodies, antibody fragments (e.g., an antigen binding portion of an antibody), antibody derivatives, and antibody analogs. The antigen binding protein can comprise, for example, an alternative protein scaffold or artificial scaffold with grafted CDRs or CDR derivatives. Such scaffolds include, but are not limited to, antibody-derived scaffolds comprising mutations introduced to, for example, stabilize the three-dimensional structure of the antigen binding protein as well as wholly synthetic scaffolds comprising, for example, a biocompatible polymer. See, for example, Korndorfer et al., 2003, Proteins: Structure, Function, and Bioinformatics, Volume 53, Issue 1:121-129 (2003); Roque et al., Biotechnol. Prog. 20:639-654 (2004). In addition, peptide antibody mimetics (“PAMs”) can be used, as well as scaffolds based on antibody mimetics utilizing fibronection components as a scaffold.

An antigen binding protein can have, for example, the structure of a naturally occurring immunoglobulin. An “immunoglobulin” is a tetrameric molecule. In a naturally occurring immunoglobulin, each tetramer is composed of two identical pairs of polypeptide chains, each pair having one “light” (about 25 kDa) and one “heavy” chain (about 50-70 kDa). The amino-terminal portion of each chain includes a variable region of about 100 to 110 or more amino acids primarily responsible for antigen recognition. The carboxy-terminal portion of each chain defines a constant region primarily responsible for effector function. Human light chains are classified as kappa and lambda light chains. Heavy chains are classified as mu, delta, gamma, alpha, or epsilon, and define the antibody's isotype as IgM, IgD, IgG, IgA, and IgE, respectively. Within light and heavy chains, the variable and constant regions are joined by a “J” region of about 12 or more amino acids, with the heavy chain also including a “D” region of about 10 more amino acids. See generally, Fundamental Immunology Ch. 7 (Paul, W., ed., 2nd ed. Raven Press, N.Y. (1989)) (incorporated by reference in its entirety for all purposes). The variable regions of each light/heavy chain pair form the antibody binding site such that an intact immunoglobulin has two binding sites.

Naturally occurring immunoglobulin chains exhibit the same general structure of relatively conserved framework regions (FR) joined by three hypervariable regions, also called complementarity determining regions or CDRs. From N-terminus to C-terminus, both light and heavy chains comprise the domains FR1, CDR1, FR2, CDR2, FR3, CDR3 and FR4. The assignment of amino acids to each domain is in accordance with the definitions of Kabat et al. in Sequences of Proteins of Immunological Interest, 5^(th) Ed., US Dept. of Health and Human Services, PHS, NIH, NIH Publication no. 91-3242, 1991.

An “antibody” refers to an intact immunoglobulin or to an antigen binding portion thereof that competes with the intact antibody for specific binding, unless otherwise specified. Antigen binding portions may be produced by recombinant DNA techniques or by enzymatic or chemical cleavage of intact antibodies. Antigen binding portions include, inter alia, Fab, Fab′, F(ab′)₂, Fv, domain antibodies (dAbs), fragments including complementarity determining regions (CDRs), single-chain antibodies (scFv), chimeric antibodies, diabodies, triabodies, tetrabodies, bispecific single chain antibodies (e.g., bispecific T-cell engagers or BiTEs), and other bispecific antibodies, and polypeptides that contain at least a portion of an immunoglobulin that is sufficient to confer specific antigen binding to the polypeptide.

The term “bispecific single chain antibody” relates to a construct comprising a first domain consisting of variable regions (or parts thereof) capable of specifically interacting with or binding to human CD3, and comprising a second domain consisting of variable regions (or parts thereof), capable of specifically interacting with or binding to human mesothelin.

A Fab fragment is a monovalent fragment having the V_(L), V_(H), C_(L) and C_(H)1 domains; a F(ab′)₂ fragment is a bivalent fragment having two Fab fragments linked by a disulfide bridge at the hinge region; a Fd fragment has the V_(H) and C_(H)1 domains; an Fv fragment has the V_(L) and V_(H) domains of a single arm of an antibody; and a dAb fragment has a V_(H) domain, a V_(L) domain, or an antigen-binding fragment of a V_(H) or V_(L) domain (U.S. Pat. Nos. 6,846,634, 6,696,245, US App. Pub. No. 05/0202512, 04/0202995, 04/0038291, 04/0009507, 03/0039958, Ward et al., Nature 341:544-546 (1989)).

A single-chain antibody (scFv) is an antibody in which a V_(L) and a V_(H) region are joined via a linker (e.g., a synthetic sequence of amino acid residues) to form a continuous protein chain wherein the linker is long enough to allow the protein chain to fold back on itself and form a monovalent antigen binding site (see, e.g., Bird et al., Science 242:423-26 (1988) and Huston et al., 1988, Proc. Natl. Acad. Sci. USA 85:5879-83 (1988)). Diabodies are bivalent antibodies comprising two polypeptide chains, wherein each polypeptide chain comprises V_(H) and V_(L) domains joined by a linker that is too short to allow for pairing between two domains on the same chain, thus allowing each domain to pair with a complementary domain on another polypeptide chain (see, e.g., Holliger et al., 1993, Proc. Natl. Acad. Sci. USA 90:6444-48 (1993), and Poljak et al., Structure 2:1121-23 (1994)). If the two polypeptide chains of a diabody are identical, then a diabody resulting from their pairing will have two identical antigen binding sites. Polypeptide chains having different sequences can be used to make a diabody with two different antigen binding sites. Similarly, tribodies and tetrabodies are antibodies comprising three and four polypeptide chains, respectively, and forming three and four antigen binding sites, respectively, which can be the same or different.

Complementarity determining regions (CDRs) and framework regions (FR) of a given antibody may be identified using the system described by Kabat et al. in Sequences of Proteins of Immunological Interest, 5th Ed., US Dept. of Health and Human Services, PHS, NIH, NIH Publication no. 91-3242, 1991. One or more CDRs may be incorporated into a molecule either covalently or noncovalently to make it an antigen binding protein. An antigen binding protein may incorporate the CDR(s) as part of a larger polypeptide chain, may covalently link the CDR(s) to another polypeptide chain, or may incorporate the CDR(s) noncovalently. The CDRs permit the antigen binding protein to specifically bind to a particular antigen of interest.

An antigen binding protein may have one or more binding sites. If there is more than one binding site, the binding sites may be identical to one another or may be different. For example, a naturally occurring human immunoglobulin typically has two identical binding sites, while a “bispecific” or “bifunctional” antibody has two different binding sites.

The term “human antibody” includes all antibodies that have one or more variable and constant regions derived from human immunoglobulin sequences. In one embodiment, all of the variable and constant domains are derived from human immunoglobulin sequences (a fully human antibody). These antibodies may be prepared in a variety of ways known in the art, nonlimiting examples of which are described herein, including through the immunization with an antigen of interest of a mouse that is genetically modified to express antibodies derived from human heavy and/or light chain-encoding genes.

A humanized antibody has a sequence that differs from the sequence of an antibody derived from a non-human species by one or more amino acid substitutions, deletions, and/or additions, such that the humanized antibody is less likely to induce an immune response, and/or induces a less severe immune response, as compared to the non-human species antibody, when it is administered to a human subject. In one embodiment, certain amino acids in the framework and constant domains of the heavy and/or light chains of the non-human species antibody are mutated to produce the humanized antibody. In another embodiment, the constant domain(s) from a human antibody are fused to the variable domain(s) of a non-human species. In another embodiment, one or more amino acid residues in one or more CDR sequences of a non-human antibody are changed to reduce the likely immunogenicity of the non-human antibody when it is administered to a human subject, wherein the changed amino acid residues either are not critical for immunospecific binding of the antibody to its antigen, or the changes to the amino acid sequence that are made are conservative changes, such that the binding of the humanized antibody to the antigen is not significantly worse than the binding of the non-human antibody to the antigen. Examples of how to make humanized antibodies may be found in U.S. Pat. Nos. 6,054,297, 5,886,152 and 5,877,293.

The term “chimeric antibody” refers to an antibody that contains one or more regions from one antibody and one or more regions from one or more other antibodies. In one embodiment, one or more of the CDRs are derived from a human anti-mesothelin antibody. In another embodiment, all of the CDRs are derived from a human anti-mesothelin antibody. In another embodiment, the CDRs from more than one human anti-mesothelin antibodies are mixed and matched in a chimeric antibody. For instance, a chimeric antibody may comprise a CDR1 from the light chain of a first human anti-mesothelin antibody, a CDR2 and a CDR3 from the light chain of a second human anti-mesothelin antibody, and the CDRs from the heavy chain from a third anti-mesothelin antibody. Further, the framework regions may be derived from one of the same anti-mesothelin antibodies, from one or more different antibodies, such as a human antibody, or from a humanized antibody. In one example of a chimeric antibody, a portion of the heavy and/or light chain is identical with, homologous to, or derived from an antibody from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is/are identical with, homologous to, or derived from an antibody or antibodies from another species or belonging to another antibody class or subclass. Also included are fragments of such antibodies that exhibit the desired biological activity (i.e., the ability to specifically bind the human mesothelin).

A “neutralizing antibody” or “inhibitory antibody” refers to an antibody that inhibits the binding of ligand to the receptor, and/or inhibits or reduces receptor signalling. The inhibition need not be complete and may be, in one embodiment, reduced binding or signalling by at least 20%. In further embodiments, the reduction in binding or signalling is at least 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 97%, 99% and 99.9%.

Fragments or analogs of antibodies can be readily prepared by those of ordinary skill in the art following the teachings of this specification and using techniques well-known in the art. Preferred amino- and carboxy-termini of fragments or analogs occur near boundaries of functional domains. Structural and functional domains can be identified by comparison of the nucleotide and/or amino acid sequence data to public or proprietary sequence databases. Computerized comparison methods can be used to identify sequence motifs or predicted protein conformation domains that occur in other proteins of known structure and/or function. Methods to identify protein sequences that fold into a known three-dimensional structure are known. See, e.g., Bowie et al., Science 253:164 (1991).

A “CDR grafted antibody” is an antibody comprising one or more CDRs derived from an antibody of a particular species or isotype and the framework of another antibody of the same or different species or isotype.

A “multi-specific antibody” is an antibody that recognizes more than one epitope on one or more antigens. A subclass of this type of antibody is a “bi-specific antibody” which recognizes two distinct epitopes on the same or different antigens.

An antigen binding protein including an antibody “specifically binds” to an antigen, such as human mesothelin if it binds to the antigen with a high binding affinity as determined by a dissociation constant (Kd, or corresponding Kb, as defined below) value of 10⁻⁷ M or less. An antigen binding protein that specifically binds to human mesothelin may be able to bind to mesothelin from other species as well with the same or different affinities.

An “epitope” is the portion of a molecule that is bound by an antigen binding protein (e.g., by an antibody). An epitope can comprise non-contiguous portions of the molecule (e.g., in a polypeptide, amino acid residues that are not contiguous in the polypeptide's primary sequence but that, in the context of the polypeptide's tertiary and quaternary structure, are near enough to each other to be bound by an antigen binding protein).

The “percent identity” of two polynucleotide or two polypeptide sequences is determined by comparing the sequences using the GAP computer program (a part of the GCG Wisconsin Package, version 10.3 (Accelrys, San Diego, Calif.)) using its default parameters.

The terms “polynucleotide,” “oligonucleotide” and “nucleic acid” are used interchangeably throughout and include DNA molecules (e.g., cDNA or genomic DNA), RNA molecules (e.g., mRNA), analogs of the DNA or RNA generated using nucleotide analogs (e.g., peptide nucleic acids and non-naturally occurring nucleotide analogs), and hybrids thereof. The nucleic acid molecule can be single-stranded or double-stranded. In one embodiment, the nucleic acid molecules of the invention comprise a contiguous open reading frame encoding an antibody, or a fragment, derivative, mutein, or variant thereof, of the invention.

Two single-stranded polynucleotides are “the complement” of each other if their sequences can be aligned in an anti-parallel orientation such that every nucleotide in one polynucleotide is opposite its complementary nucleotide in the other polynucleotide, without the introduction of gaps, and without unpaired nucleotides at the 5′ or the 3′ end of either sequence. A polynucleotide is “complementary” to another polynucleotide if the two polynucleotides can hybridize to one another under moderately stringent conditions. Thus, a polynucleotide can be complementary to another polynucleotide without being its complement.

A “vector” is a nucleic acid that can be used to introduce another nucleic acid linked to it into a cell. One type of vector is a “plasmid,” which refers to a linear or circular double stranded DNA molecule into which additional nucleic acid segments can be ligated. Another type of vector is a viral vector (e.g., replication defective retroviruses, adenoviruses and adeno-associated viruses), wherein additional DNA segments can be introduced into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors comprising a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) are integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. An “expression vector” is a type of vector that can direct the expression of a chosen polynucleotide.

A nucleotide sequence is “operably linked” to a regulatory sequence if the regulatory sequence affects the expression (e.g., the level, timing, or location of expression) of the nucleotide sequence. A “regulatory sequence” is a nucleic acid that affects the expression (e.g., the level, timing, or location of expression) of a nucleic acid to which it is operably linked. The regulatory sequence can, for example, exert its effects directly on the regulated nucleic acid, or through the action of one or more other molecules (e.g., polypeptides that bind to the regulatory sequence and/or the nucleic acid). Examples of regulatory sequences include promoters, enhancers and other expression control elements (e.g., polyadenylation signals). Further examples of regulatory sequences are described in, for example, Goeddel, 1990, Gene Expression Technology: Methods in Enzymology 185, Academic Press, San Diego, Calif. and Baron et al., 1995, Nucleic Acids Res. 23:3605-06.

A “host cell” is a cell that can be used to express a nucleic acid, e.g., a nucleic acid of the invention. A host cell can be a prokaryote, for example, E. coli, or it can be a eukaryote, for example, a single-celled eukaryote (e.g., a yeast or other fungus), a plant cell (e.g., a tobacco or tomato plant cell), an animal cell (e.g., a human cell, a monkey cell, a hamster cell, a rat cell, a mouse cell, or an insect cell) or a hybridoma. Typically, a host cell is a cultured cell that can be transformed or transfected with a polypeptide-encoding nucleic acid, which can then be expressed in the host cell. The phrase “recombinant host cell” can be used to denote a host cell that has been transformed or transfected with a nucleic acid to be expressed. A host cell also can be a cell that comprises the nucleic acid but does not express it at a desired level unless a regulatory sequence is introduced into the host cell such that it becomes operably linked with the nucleic acid. It is understood that the term host cell refers not only to the particular subject cell but to the progeny or potential progeny of such a cell. Because certain modifications may occur in succeeding generations due to, e.g., mutation or environmental influence, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term as used herein.

As used herein, a “non-chimpanzee primate” or “non-chimp primate” or grammatical variants thereof refers to any primate other than chimpanzee, i.e. other than an animal of belonging to the genus Pan, and including the species Pan paniscus and Pan troglodytes, also known as Anthropopithecus troglodytes or Simia satyrus. Most preferred is Macaca fascicularis (also known as Cynomolgus monkey and, therefore, throughout the application alternatively referred to as “Cynomolgus”) and Macaca mulatta (rhesus monkey, or “rhesus”).

In one embodiment, the antigen binding proteins of the present invention may be selected to bind to membrane-bound mesothelin as expressed on cells. In certain embodiments, the antigen binding proteins of the present invention preferentially bind membrane-bound mesothelin over soluble mesothelin. In one embodiment, the antigen binding proteins bind membrane-bound mesothelin at least 5 fold, 10 fold, 15 fold, 20 fold, 25 fold, 30 fold, 40 fold, 50 fold, 100 fold, 500 fold, or 1000 fold greater than soluble mesothelin. In one embodiment, the antigen binding proteins of the present invention preferentially bind membrane-bound mesothelin 30 fold greater than soluble mesothelin.

In one embodiment, the antigen binding proteins of the present invention specifically bind to human mesothelin. In a further embodiment, the antigen binding proteins binding to human mesothelin may also bind to mesothelin of other species. In one embodiment, the antigen binding proteins of the present invention bind to human, cynomologous and murine mesothelin.

The polynucleotide and polypeptide sequences for several species of mesothelin are known. Table 1 presents nonlimiting, representative examples of sequences for human, mouse, rat, and nonhuman primate (e.g., cynomolgus). Additional examples are readily found in publicly available databases (e.g., NCBI).

TABLE 1 Mesothelin Sequences Human (Homo sapiens) polynucleotides (SEQ ID NO: 1) NCBI Reference Sequence: NM_005823.5 (Variant 1) TGCCAGGCTCTCCACCCCCACTTCCCAATTGAGGAAACCGAGGCAGAGGAGGCTCAGCGCCACGCACTCC TCTTTCTGCCTGGCCGGCCACTCCCGTCTGCTGTGACGCGCGGACAGAGAGCTACCGGTGGACCCACGGT GCCTCCCTCCCTGGGATCTACACAGACCATGGCCTTGCCAACGGCTCGACCCCTGTTGGGGTCCTGTGGG ACCCCCGCCCTCGGCAGCCTCCTGTTCCTGCTCTTCAGCCTCGGATGGGTGCAGCCCTCGAGGACCCTGG CTGGAGAGACAGGGCAGGAGGCTGCGCCCCTGGACGGAGTCCTGGCCAACCCACCTAACATTTCCAGCCT CTCCCCTCGCCAACTCCTTGGCTTCCCGTGTGCGGAGGTGTCCGGCCTGAGCACGGAGCGTGTCCGGGAG CTGGCTGTGGCCTTGGCACAGAAGAATGTCAAGCTCTCAACAGAGCAGCTGCGCTGTCTGGCTCACCGGC TCTCTGAGCCCCCCGAGGACCTGGACGCCCTCCCATTGGACCTGCTGCTATTCCTCAACCCAGATGCGTT CTCGGGGCCCCAGGCCTGCACCCGTTTCTTCTCCCGCATCACGAAGGCCAATGTGGACCTGCTCCCGAGG GGGGCTCCCGAGCGACAGCGGCTGCTGCCTGCGGCTCTGGCCTGCTGGGGTGTGCGGGGGTCTCTGCTGA GCGAGGCTGATGTGCGGGCTCTGGGAGGCCTGGCTTGCGACCTGCCTGGGCGCTTTGTGGCCGAGTCGGC CGAAGTGCTGCTACCCCGGCTGGTGAGCTGCCCGGGACCCCTGGACCAGGACCAGCAGGAGGCAGCCAGG GCGGCTCTGCAGGGCGGGGGACCCCCCTACGGCCCCCCGTCGACATGGTCTGTCTCCACGATGGACGCTC TGCGGGGCCTGCTGCCCGTGCTGGGCCAGCCCATCATCCGCAGCATCCCGCAGGGCATCGTGGCCGCGTG GCGGCAACGCTCCTCTCGGGACCCATCCTGGCGGCAGCCTGAACGGACCATCCTCCGGCCGCGGTTCCGG CGGGAAGTGGAGAAGACAGCCTGTCCTTCAGGCAAGAAGGCCCGCGAGATAGACGAGAGCCTCATCTTCT ACAAGAAGTGGGAGCTGGAAGCCTGCGTGGATGCGGCCCTGCTGGCCACCCAGATGGACCGCGTGAACGC CATCCCCTTCACCTACGAGCAGCTGGACGTCCTAAAGCATAAACTGGATGAGCTCTACCCACAAGGTTAC CCCGAGTCTGTGATCCAGCACCTGGGCTACCTCTTCCTCAAGATGAGCCCTGAGGACATTCGCAAGTGGA ATGTGACGTCCCTGGAGACCCTGAAGGCTTTGCTTGAAGTCAACAAAGGGCACGAAATGAGTCCTCAGGT GGCCACCCTGATCGACCGCTTTGTGAAGGGAAGGGGCCAGCTAGACAAAGACACCCTAGACACCCTGACC GCCTTCTACCCTGGGTACCTGTGCTCCCTCAGCCCCGAGGAGCTGAGCTCCGTGCCCCCCAGCAGCATCT GGGCGGTCAGGCCCCAGGACCTGGACACGTGTGACCCAAGGCAGCTGGACGTCCTCTATCCCAAGGCCCG CCTTGCTTTCCAGAACATGAACGGGTCCGAATACTTCGTGAAGATCCAGTCCTTCCTGGGTGGGGCCCCC ACGGAGGATTTGAAGGCGCTCAGTCAGCAGAATGTGAGCATGGACTTGGCCACGTTCATGAAGCTGCGGA CGGATGCGGTGCTGCCGTTGACTGTGGCTGAGGTGCAGAAACTTCTGGGACCCCACGTGGAGGGCCTGAA GGCGGAGGAGCGGCACCGCCCGGTGCGGGACTGGATCCTACGGCAGCGGCAGGACGACCTGGACACGCTG GGGCTGGGGCTACAGGGCGGCATCCCCAACGGCTACCTGGTCCTAGACCTCAGCATGCAAGAGGCCCTCT CGGGGACGCCCTGCCTCCTAGGACCTGGACCTGTTCTCACCGTCCTGGCACTGCTCCTAGCCTCCACCCT GGCCTGAGGGCCCCACTCCCTTGCTGGCCCCAGCCCTGCTGGGGATCCCCGCCTGGCCAGGAGCAGGCAC GGGTGGTCCCCGTTCCACCCCAAGAGAACTCGCGCTCAGTAAACGGGAACATGCCCCCTGCAGACACGTA AAAAAAAAAAAAAAAAA Human (Homo sapiens) amino acid (SEQ ID NO: 2) GenB ank: BAA08419.1; GenBank: AAH09272.1 MALPTARPLLGSCGTPALGSLLFLLFSLGWVQPSRTLAGETGQEAAPLDGVLANPPNISS LSPRQLLGFPCAEVSGLSTERVRELAVALAQKNVKLSTEQLRCLAHRLSEPPEDLDALPL DLLLFLNPDAFSGPQACTREFSRITKANVDLLPRGAPERQRLLPAALACWGVRGSLLSEA DVRALGGLACDLPGRFVAESAEVLLPRLVSCPGPLDQDQQEAARAALQGGGPPYGPPSTW SVSTMDALRGLLPVLGQPIIRSIPQGIVAAWRQRSSRDPSWRQPERTILRPRFRREVEKT ACPSGKKAREIDESLIFYKKWELEACVDAALLATQMDRVNAIPFTYEQLDVLKHKLDELY PQGYPESVIQHLGYLFLKMSPEDIRKWNVTSLETLKALLEVNKGHEMSPQAPRRPLPQVA TLIDRFVKGRGQLDKDTLDTLTAFYPGYLCSLSPEELSSVPPSSIWAVRPQDLDTCDPRQ LDVLYPKARLAFQNMNGSEYFVKIQSFLGGAPTEDLKALSQQNVSMDLATFMKLRTDAVL PLTVAEVQKLLGPHVEGLKAEERHRPVRDWILRQRQDDLDTLGLGLQGGIPNGYLVLDLS MQEALSGTPCLLGPGPVLTVLALLLASTLA Mouse (Mus musculus) polynucleotide (SEQ ID NO: 3) NCBI Reference Sequence: NM_018857.1 GGACAGCTGCTTTCCCAGGCCCAAAAGCCCCTTCGTTGTCTCCAAACAGTGGTGTGGGTTGAGGGGTGGG ACAAGTGGGGACCTCAGAGTCATTGTTATCCACAGACCATGGCCTTGCCAACAGCTCGACCCCTGCTGGG GTCCTGTGGAAGTCCCATCTGCAGCCGAAGCTTCCTACTGCTTCTCCTTAGTCTTGGGTGGATACCACGT CTGCAGACCCAGACTACAAAGACAAGCCAGGAGGCCACACTCCTCCATGCTGTGAACGGTGCCGCTGACT TTGCCAGTCTCCCCACAGGCCTCTTTCTTGGCCTCACATGTGAGGAGGTATCTGACCTGAGCATGGAACA AGCCAAGGGGCTGGCTATGGCTGTAAGACAGAAGAACATTACACTCCGGGGACATCAGCTGCGTTGTCTG GCACGTCGCCTTCCTAGGCACCTCACCGACGAGGAACTGAATGCTCTTCCACTGGACCTGCTGCTCTTCC TCAACCCAGCCATGTTTCCAGGGCAACAGGCTTGTGCCCACTTCTTCTCCCTCATCTCTAAAGCCAATGT GGATGTACTCCCACGGAGGTCTCTGGAGCGCCAGAGGCTGCTGATGGAGGCTCTGAAGTGCCAGGGCGTG TATGGATTTCAAGTGAGTGAGGCAGATGTGCGGGCTCTCGGAGGCCTGGCCTGTGACCTGCCTGGGAAAT TTGTGGCCAGATCTTCCGAAGTTCTCCTCCCCTGGCTGGCAGGATGCCAAGGACCCCTGGACCAGAGCCA GGAAAAGGCAGTCAGGGAGGTTCTGAGGAGTGGAAGAACCCAATATGGCCCCCCATCGAAGTGGTCAGTC TCCACCCTGGATGCCCTGCAGAGCTTGGTAGCAGTGTTGGATGAGTCCATCGTCCAGAGCATCCCCAAGG ATGTCAAAGCTGAATGGCTGCAACACATCTCCAGAGACCCCTCCAGGCTGGGGTCTAAGCTGACCGTCAT ACACCCAAGGTTCCGACGGGATGCAGAACAGAAAGCCTGCCCTCCAGGGAAGGAGCCCTACAAGGTGGAT GAAGACCTCATCTTCTACCAGAATTGGGAGCTGGAGGCTTGTGTAGATGGCACCATGCTGGCCAGACAAA TGGACCTTGTGAACGAGATTCCCTTCACCTATGAGCAGCTCAGTATCTTTAAGCACAAACTGGACAAGAC CTACCCACAAGGCTATCCTGAGTCCCTGATCCAGCAGCTGGGTCACTTCTTCAGATATGTTAGCCCTGAA GACATCCACCAGTGGAATGTGACCTCACCAGACACAGTGAAAACTCTGCTCAAAGTCAGCAAAGGACAAA AGATGAATGCTCAGGCGATTGCCTTGGTCGCCTGCTATCTTCGGGGAGGAGGCCAGCTGGACGAGGATAT GGTAAAAGCCCTGGGCGACATCCCGTTAAGCTATCTATGTGACTTCAGCCCCCAGGATCTGCACTCGGTA CCCTCCAGTGTCATGTGGCTGGTTGGGCCCCAAGACCTGGACAAGTGCAGCCAGAGGCATCTGGGTCTCC TCTACCAGAAGGCCTGCTCAGCCTTCCAGAATGTGAGCGGCCTAGAATACTTTGAGAAAATCAAGACATT CCTGGGTGGGGCCTCCGTGAAGGACCTGCGGGCCCTCAGCCAGCACAATGTGAGCATGGACATAGCCACT TTCAAGAGGCTGCAGGTGGATTCCCTGGTGGGGCTGAGTGTGGCTGAGGTACAGAAACTTCTGGGGCCAA ACATTGTGGACCTGAAGACCGAGGAGGATAAAAGCCCTGTCCGTGACTGGCTGTTCCGGCAGCATCAGAA AGACCTAGACAGGCTGGGTTTGGGACTTCAGGGTGGCATCCCCAATGGCTACCTGGTCCTGGACTTCAAT GTCCGAGAGGCCTTCTCCAGCAGAGCCTCACTCCTTGGGCCAGGATTTGTATTAATATGGATTCCAGCTC TGCTCCCAGCTTTAAGGCTGAGCTGAGACCACCACCCTGCAAGGCTCCTGGTCCCAGCTCTACTGGGGCC CTCTTGACCAGGAGTGGGTACCAGGGGTCATTGCCAAAGTTTGAGGACTCTTGAACTCAATAAACAGTGG CATATGCTCCCTTGAAAAAAAAAAAAAAAAAAAAA Mouse (Mus musculus) amino acid (SEQ ID NO: 4) GenBank: EDL22444.1 MALPTARPLLGSCGSPICSRSFLLLLLSLGWIPRLQTQTTKTSQEATLLHAVNGAADFASLPTGLFLGLT CEEVSDLSMEQAKGLAMAVRQKNITLRGHQLRCLARRLPRHLTDEELNALPLDLLLFLNPAMFPGQQACA HFFSLISKANVDVLPRRSLERQRLLMEALKCQGVYGFQVSEADVRALGGLACDLPGKFVARSSEVLLPWL AGCQGPLDQSQEKAVREVLRSGRTQYGPPSKWSVSTLDALQSLVAVLDESIVQSIPKDVKAEWLQHISRD PSRLGSKLTVIHPRFRRDAEQKACPPGKEPYKVDEDLIFYQNWELEACVDGTMLARQMDLVNEIPFTYEQ LSIFKHKLDKTYPQGYPESLIQQLGHFFRYVSPEDIHQWNVTSPDTVKTLLKVSKGQKMNAQAIALVACY LRGGGQLDEDMVKALGDIPLSYLCDFSPQDLHSVPSSVMWLVGPQDLDKCSQRHLGLLYQKACSAFQNVS GLEYFEKIKTFLGGASVKDLRALSQHNVSMDIATFKRLQVDSLVGLSVAEVQKLLGPNIVDLKTEEDKSP VRDWLFRQHQKDLDRLGLGLQGGIPNGYLVLDFNVREAFSSRASLLGPGFVLIWIPALLPALRLS Rat (Rattus norvegicus) polynucleotide (SEQ ID NO: 5) GenBank: D87351.1 TGCCAACAGGCCCCTCACTGTGTCCAAACAGTGGTGTGAGTTGAGGGGTGGGACAGGTGGGGACCTCAGA ACCATTGTTATCCACAGACCATGGCCTTGCCAACAGCCCAACCCCTGCTGGGGTCCTGTGGAAGCCCCAT CTGCAGCCGCAGCTTTCTACTGCTTCTCCTTAGTCTTGGGTGGTTGCCACTTCTGCAGACCCAGACTACA AGGACAAGCCAGGAGGCCGCACTTCTCCATGCTGTGACCGGCACCGTTGACTTTGCCAGTCTTCCCACAG GCCTCTTTCTTGGCCTCACGTGTGATGAGGTATCTGGCCTAAGCATGGGACACGCCAAGGAGCTGGCTAT GGCTGTGAGACAGAAGAATATCGTGCTCCAAGTACATCAGCTGCGCTGTCTGGCCCGTCGCCTCCCTAAG CACCTCACCAACGAGGAACTGGATGCTCTCCCACTGGACCTGCTGCTCTTCCTCAATCCAGCCATGTTTC CGGGGCAACAGGCTTGTGCCCACTTCTTCTCCCTCATCTCTAAAGCCAATGTAAATGTACTCCCACGGAG ATCTCTGGAGCGCCAGAGGCTGCTGACCGGGGCTCTGAAATGCCAGGGTGTGTATGGATTTCAAGTGAGT GAGACGGATGCACGGGCTCTCGGAGGCCTGGCCTGTGACCTGCCTGGGGAATTCGTGGCCAAATCTTCGG AAGTCCTCCTCCCCTGGCTGGCAAGATGCGGAGGACCCCTGGACCAAGGCCAGGCAAAGGCTGTCAGGGA GGTTCTGAGGAGTGGAAGAGCCCCCTATGGTCCCCCATCGACGTGGTCAGTCTCCACCCTGGATGCCCTG CAGGGTTTGCTGGTAGTGTTGGATGAGTCCATTGTCCACAGCATCCCTAAGGATGTTATCACTGAATGGC TGCAAGGCATCTCCAGAGAGCCCTCCAGGCTGGGGTCTAAGTGGACTGTCACACACCCAAGGTTCCGGCG GGACACAGAACAGAAAGCCTGCCCTCCAGGGAAGGAGCCTAACGTGGTGGATGAAAACCTCATCTTCTAC CAGAATTGGGAGCTGGAGGCTTGTGTCGATGGTACCCTGCTGGCCGGCCAGATGGACCTTGTGAATGAAA TTCCCTTTACCTACGAGCAGCTCAGCATCTTCAAGCACAAACTGGACAAGACCTACCCACAAGGCTATCC CGAGTCCCTGATCAAGCAGCTGGGCCACTTCTTCAGATACGTTAGCCCTGAGGACATCCGGCAGTGGAAT GTGACTTCACCAGACACAGTGAATACTCTGCTTAAAGTCAGCAAAGGACAAAAGATGGATGCTCAGGTGA TTGCCTTGGTCGCCTGCTATCTTCGGGGAGGAGGCAAGCTGGACGAGGACATAGTAAAAGCCCTGGACAA CATCCCCTTAAGTTACCTATGTGACTTCAGCCCCCAGGATCTGCACGCTATACCCTCCAGTGTTATGTGG CTGGTTGGGCTCCATGACCTGGACAAGTGCAGCCAGAGGCATCTGGGTATCCTCTATCAGAAGGCCTGCT CAGCCTTCCAGAACGTGAGCGGGCTGGAATACTTTGAGAAAATCAGGACATTTCTGGGTGGGGCCTCCAG GGAGGACCTGCGGGCCCTCAGCCAGCACAATGTGAGTATGGACATAGCCACTTTCAAGAAGCTGCAGGTG GATGCCCTGGTGGGGCTGAGTGTGGCTGAGGTACAGAAACTTCTAGGGCCACACATTGGGGACCTGAAGA CTGAGGAGGATAAAAGCCCTGTCCGGGACTGGCTCTTCCGACAGCAGCAGAAAGACCTGGACAGTCTGGG TTTGGGACTTCAGGGTGGCATCCCCAATGGCTACCTGATCCTAGACTTCAATGTCCGAGAGGCCTTCTCC AGTGGAGCCCCACTCCTTGGGCCAGGATTTGTGTTTGCATGGATTCCAGCTCTGCTCTCAGCTTTAAGAC TGAGCTGAGACCACCACTCCTAAGGCTCCTGGTCCCAGCTCTATTGTCGAGCCCCATCTTGACCAGGAGG GGATACCAGGGGTCATTGCCAAAGTTTGAGGATTCTTGAACCCAATAAACAGTGGCATGTGCCCCCTTG Rat (Rattus norvegicus) amino acid (SEQ ID NO: 6) GenBank: EDM03949.1 MALPTAQPLLGSCGSPICSRSFLLLLLSLGWLPLLQTQTTRTSQEAALLHAVTGTVDFASLPTGLFLGLM CDEVSGLSMGHAKELAMAVRQKNIVLQVHQLRCLARRLPKHLTNEELDALPLDLLLFLNPAMFPGQQACA HFFSLISKANVNVLPRRSLERQRLLTGALKCQGVYGFQVSETDARALGGLACDLPGEFVAKSSEVLLPWL ARCGGPLDQGQAKAVREVLRSGRAPYGPPSTWSVSTLDALQGLLVVLDESIVHSIPKDVITEWLQGISRE PSRLGSKWTVTHPRFRRDTEQKACPPGKEPNVVDENLIFYQNWELEACVDGTLLAGQMDLVNEIPFTYEQ LSIFKHKLDKTYPQGYPESLIKQLGHFFRYVSPEDIRQWNVTSPDTVNTLLKVSKGQKMDAQVIALVACY LRGGGKLDEDIVKALDNIPLSYLCDFSPQDLHAIPSSVMWLVGLHDLDKCSQRHLGILYQKACSAFQNVS GLEYFEKIRTFLGGASREDLRALSQHNVSMDIATFKKLQVDALVGLSVAEVQKLLGPHIGDLKTEEDKSP VRDWLFRQQQKDLDSLGLGLQGGIPNGYLILDFNVREAFSSGAPLLGPGFVFAWIPALLSALRLS Cynomolgus (Macaca mulatta) polynucleotides (SEQ ID NO: 7) NCBI Reference Sequence: XM_001087333.2 (predicted) ATGGCCTTGCCAATGGCTCGACCCCTGTCGGGGTCCTGTGGGACCCCCGCCCTCGGCAGCCTCCTGTTCC TGCTCTTCAGCCTCGGATGGGTGCAGCCCTCGAGGGTCCTGGCTGGAGAGACAAGGCAGGCCGCGCCCCT GGATGGAATCCTGACCAATGCACCTGACATTGCCAGCCTCTCCCCACGCCAACTCCTTGGCTTCACGTGT GTGGAGGTGTCCGGCCTGAGCACAGAGCTCGTCCAGGAGCTGGCTGTGGCCTTGGGACAGAAGAATGTCA AGCTCTCCGCAGAGCAGCTGCGCTGTCTGGCTCACCAGCTCTCTGAGCCCCCCGAGGACCTGGACGCCCT CCCGCTGGACCTGCTGCTCTTCCTCAACCCAGACGCGTTCTCGGGGCCCCAGGCCTGCACCCACTTCTTC TCCCGCGTCGCGAAGGCCAACGTGGACCTGCTCCCGCGGGGGGCTCCTGAGAGACAGAGGCTGCTGCCCG GGGCTCTGACCTGCTGGGGTGTGCGGGGGTCTCTGCTGAGCGAGGCTGATGTACGGGCTCTGGGAGGCCT GGCTTGCGACCTGCCTGGGCGCTTTGTGGCCGAGTCGGCAGAAGTGGTGCTACCCCGGCTGGTCCGCTGC TTGGGACCCCTGGACCAGGACCAGCAGGAAGCAGCCAGGGCGGCTCTGCAGAGAGGAGGACCCCCCTACG GCCCCCCGTCAACGTGGTCTATCTCCACCCTGGACGATCTGCAGAGCCTGTTGCCTGTGCTGGGCCAGCC CGTCATCTCTGCTCGTCCTCAGGGCATCCTGGCCGCATGGCGGCAACGCTCCTCTCGGGACCCATCCTGG CAGCAGCCGGAACAGACCGTCCTCCGGCTGAGGTTCCGGCGGGACGTGGAGAGGACAACCTGTCCCCCAG AGAAAGAGGTCCACGAGATAGACGAGAGCCTCATCTTCTACAAGAAGCGGGAGCTGGAAGCCTGCGTGGA CCCAGCCCTGCTGGCCGCCCAGATGGACCGTGTGGACGCCATCCCCTTCACCTACGAGCAGCTGGACGTC CTAAAGCATAAACTGGATGAGCTCTACCCACAAGGCTACCCCGAGTCTGTGATCCGGCACCTGGGCCACC TCTTCCTCAAGATGAGCCCTGAGGACATTCGCAAATGGAACGTGACGTCCCTGGAGACCCTGAAGGCTCT GCTCAAAGTCAGCAAGGGGCATGAAATGAGTGCTCAGGTGGCCACCCTGATTGACCGCGTTGTGGTGGGA AGGGGCCAGCTAGACAAAGACACCGTAGACACGCTGACTGCCTTCTGCCCCGGGTGCCTGTGCTCCCTCA GCCCCGAGAGGCTGAGCTCCGTGCCCCCCAGCGTCATCGGGGCGGTCAGGCCCCAGGACCTGGACACGTG TGGCCCGAGGCAGCTGGACGTCCTCTATCCCAAGGCCCGCCTTGCTTTCCAGAACATGAGCGGGTCCGAA TACTTCGTGAAGATCCGGCCCTTCCTGGGTGGGGCCCCCACGGAGGATGTGAAGGCTCTCAGTCAGCAGA ATGTGAGCATGGACTTGGCCACGTTCATGAAGCTGCGGAGGGAAGCGGTGCTGCCGTTGACTGTGGCTGA AGTGCAGAAACTTCTGGGACCCCACGTGGAGGGCCTGAAGGTGGAGGAGCAGCACAGCCCCGTGCGGGAC TGGATCCTAAAGCAGCGGCAGGACGACCTGGACACACTGGGGCTGGGGCTACAGGGCGGCATCCCCAACG GCTACCTGATCCTAGACCTCAGTGTGCGAGAGGCCCTCTCGGGGACGCCCTGCCTCCTAGGACCTGGACC TGTACTCACCGTCCTGGCTTTGCTCCTGGCCTCCACCCTGGCCTGAGGACCCTACTCCCTTGCTGGCCCC AGCCCTGCTGGGGATCCCCGCCTGGCCAGGAGCAGGCATAGGTGGTCCCTGTTCCACCCCAGGAGAACTT GCGCTCAGTAAACGCGAACATGCCCCCT Cynomolgus (Macaca fascicularis) amino acid (SEQ ID NO: 8) (partial hypothetical) GenBank: EHH60027.1 MALPMARPLSGSCGTPALGSLLFLLFSLGWVQPSRVLAGETRQEAAPLDGILTNAPDIASLSPRQLLGFT CVEVSGLSTELVQELAVALGQKNVKLSAEQLRCLAHRLSEPPEDLDALPLDLLLFLKQASVQGVRGSLLS EADVRALGGLACDLPGRFVAESAEVVLPRLVRCLGPLDQDQQEAARAALQRGGPPYGPPSTWSISTLDDL QSLLPVLGQPVIHSIPQGILAAWRQRSSRDPSWQQPEQTVLRPRFRRDVERTTCPPEKEVHEIDENLIFY KKRELEACVDAALLAAQMDRVDAIPFTYEQLDVLKHKLDELYPQGYPESVIRHLGHLFLKMSPEDIRKWN VTSLETLKALLKVSKGHEMSAQVATLIDRVVVGRGQLDKDTADTLTAFCPGCLCSLSPERLRSVPPSVIG AVRPQDLDTCGPRQLDVLYPKARLAFQNMSGSEYFVKIRPFLGGAPTEDLKALSQQNVSMDLATFMKLRR EAVLVGRAGGGASGGGDNRGREGV Antigen Binding Proteins

In referring to the different antigen binding proteins of the invention, arbitrary designations have been given to identify the different antigen binding proteins (e.g., “ab237”). In some instances, the designation may have variations for the same antigen binding proteins (e.g., “ab237” “237”, or “2.37” all refer to the same antigen binding protein).

In one aspect, the present invention provides antigen binding proteins (e.g., antibodies, antibody fragments, antibody derivatives, antibody muteins, and antibody variants), that specifically bind to human mesothelin. In one embodiment the antigen binding protein is a human antibody.

In one embodiment, the antigen binding protein (e.g., antibody) comprises sequences that each independently differ by 5, 4, 3, 2, 1, or 0 single amino acid additions, substitutions, and/or deletions from a CDR sequence of those listed in Table 2 below. As used herein, a CDR sequence that differs by no more than a total of, for example, four amino acid additions, substitutions and/or deletions from a CDR sequence shown in Table 2 below refers to a sequence with 4, 3, 2, 1 or 0 single amino acid additions, substitutions, and/or deletions compared with the sequences shown in Table 2.

The amino acid sequences of light chain CDRs of exemplary antigen binding proteins (antibodies) and the heavy chain CDRs of exemplary antigen binding proteins (antibodies) are shown below in Table 2.

TABLE 2 LIGHT CHAIN CDR AMINO ACID SEQUENCES Ab CDR 1 CDR 2 CDR 3 Ab237 RASQSINNYLN AASSLQS QQTYSNPT AA (SEQ ID NO: 9) (SEQ ID NO: 10) (SEQ ID NO: 11) Ab1.1.2 RASQYIGSNLH YASQSFS HQSSSLPWT AA (SEQ ID NO: 12) (SEQ ID NO: 13) (SEQ ID NO: 14) Ab1.33.1 QSSLSLQHSNGKTYLY EVSNRFS MQSKQLPCS AA (SEQ ID NO: 15) (SEQ ID NO: 16) (SEQ ID NO: 17) Ab1.33.1y QSSLSLQHSNGKTYLY EVSNRFS MQSKQLPYS AA (SEQ ID NO: 18) (SEQ ID NO: 19) (SEQ ID NO: 20) Ab1.68.1 RASQTVSSSYLA GAS IRAT QQYGSSLT AA (SEQ ID NO: 21) (SEQ ID NO: 22) (SEQ ID NO: 23) Ab1.78.1 RASQSIGSSLH YASQSFS HQSSSLPWT AA (SEQ ID NO: 24) (SEQ ID NO: 25) (SEQ ID NO: 26) Ab1.119.1 RSSQSLVHSDRNTYLS KISNRFS MQATQFPLT AA (SEQ ID NO: 27) (SEQ ID NO: 28) (SEQ ID NO: 29) Ab2.69.2 RSSLSLLHSNGYNYLD LGSNRAS MQGLHTPPS AA (SEQ ID NO: 30) (SEQ ID NO: 31) (SEQ ID NO: 32) Ab2.69.2-cv QASQDISNYLN AASSLET QQYDNLP AA (SEQ ID NO: 33) (SEQ ID NO: 34) (SEQ ID NO: 35) Ab2.69.2-s QASQDISNYLN AASSLET QQYDNLP AA (SEQ ID NO: 36) (SEQ ID NO: 37) (SEQ ID NO: 38) Ab1.58 RASQGIRNALG AASSLQS LQHNSYPRT (SEQ ID NO: 39) (SEQ ID NO: 40) (SEQ ID NO: 41) Ab1.51 RASQGIRNDLH AASSLQS LQHYSYPWT (SEQ ID NO: 42) (SEQ ID NO: 43) (SEQ ID NO: 44) HEAVY CHAINS CDR AMINO ACID SEQUENCES Ab CDR 1 CDR 2 CDR 3 Ab237 NNNYYWT YIYYSGSTFYNPSLKS EDTMTGLDV AA (SEQ ID NO: 45) (SEQ ID NO: 46) (SEQ ID NO: 47) Ab1.1.2 SYGMH AIWYDGSNKYYADSVKG DLSIFGVVILSDY AA (SEQ ID NO: 48) (SEQ ID NO: 49) (SEQ ID NO: 50) Ab1.33.1 GDGHFWS YIYYSGSTYYNPSLKS LRGGYKFDY AA (SEQ ID NO: 51) (SEQ ID NO: 52) (SEQ ID NO: 53) Ab1.68.1 NYYWS RIFTSGSTNYNPSLKS EGGHYGSSGYLYYYYFGMDV AA (SEQ ID NO: 54) (SEQ ID NO: 55) (SEQ ID NO: 56) Ab1.78.1 SYGMH AIWYDGSNKYYADSVKG DLSIFGVVILSDY AA (SEQ ID NO: 57) (SEQ ID NO: 58) (SEQ ID NO: 59) Ab1.119.1 SGGYYWN YIYYSGSTYYNPSLRG DGGDSYGRMDV AA (SEQ ID NO: 60) (SEQ ID NO: 61) (SEQ ID NO: 62) Ab2.69.2 SNSVAWN RTYYRSKWYNDYAVSVKS GIFVVPAVPRFDY AA (SEQ ID NO: 63) (SEQ ID NO: 64) (SEQ ID NO: 65) Ab1.58 SHYWS YIYYSGSTNYNPSLKS DGWSAFDY (SEQ ID NO: 66) (SEQ ID NO: 67) (SEQ ID NO: 68) Ab1.51 SYYWS YIYYSGSTNYNPSLKS VDYKAFDI (SEQ ID NO: 69) (SEQ ID NO: 70) (SEQ ID NO: 71)

Table 3 below also provides the amino acid sequences of the variable light and variable heavy domains for exemplary anti-mesothelin antibodies.

TABLE 3 Anti-Mesothelin Variable Region Amino Acid Sequences Light Chain Variable Region Polynucleotide and Amino acid sequences Ab237 DIQMTQSPSSLSASVGDRVTITCRASQSINNYLNWYQQKPGKAPTLLIYA ASSLQSGVPSRFSGSRSGTDFTLTISSLQPEDFAAYFCQQTYSNPTFGQG TKVEVK (SEQ ID NO: 72) Ab1.1.2 EIVLTQSPDFQSVTPKEKVTITCRASQYIGSNLHWYQQTPDQSPKLLIKY ASQSFSGVPSRFSGSGSGTDFTLTINSLEAEDAATYYCHQSSSLPWTFGQ GTKVEIK (SEQ ID NO: 73) Ab1.33.1 DIVMTQTPLSLSVAPGQPASISCQSSLSLQHSNGKTYLYWYLQKPGQPPQ LLIYEVSNRFSGVPDRFSGSGSGTDFTLKISRVEAEDVGIYYCMQSKQLP CSFGQGTKLEIK (SEQ ID NO: 74) Ab1.33.1-y DIVMTQTPLSLSVAPGQPASISCQSSLSLQHSNGKTYLYWYLQKPGQPPQ LLIYEVSNRFSGVPDRFSGSGSGTDFTLKISRVEAEDVGIYYCMQSKQLP YSFGQGTKLEIK (SEQ ID NO: 75) Ab1.68.1 EIVLTQSPGTLSLSPGERATLSCRASQTVSSSYLAWYQQKPGQAPRLLIY GASIRATGIPDRFSGSGSGTDFTLTISRLEPEDFAVYYCQQYGSSLTFGG GTKVEIK (SEQ ID NO: 76) Ab1.78.1 EIVLTQSPDFQSVTPKEKVTITCRASQSIGSSLHWYRQKPDQSPKLLIKY ASQSFSGVPSRFSGGGSGTDFTLTINSLEAEDAATYYCHQSSSLPWTFGQ GTKVEIK (SEQ ID NO: 77) Ab1.119.1 DIVMTQTPLSSPVTLGQPASISCRSSQSLVHSDRNTYLSWLQQRPGQPPR LLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQATQFP LTFGGGTKVEIK (SEQ ID NO: 78) Ab2.69.2 DIVMTQSPLSLSVTPGEPASISCRSSLSLLHSNGYNYLDWFLQKPGQSPQ LLIYLGSNRASGVPDRFSGSGSDTDFTLKISRVEAEDVGVYYCMQGLHTP PSFGQGTKLEIK (SEQ ID NO: 79) Ab2.69.2-s DIQMTQSPSSLSASVGDRVTITCQASQDISNYLNWYQQKPGKAPNLLIYA ASSLETGVPSRFSGGGSGTDFAFTISSLQPEDIAPYYCQQYDNLPFGPGT KVDIK (SEQ ID NO: 80) Ab2.69.2-cv DIQMTQSPSSLSASVGDRVTITCQASQDISNYLNWYQQKPGKAPKLLIYA ASSLETGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYDNLPFGQGT KVDIK (SEQ ID NO: 81) Ab1.58 DIQMTQSPSSLSASVGDRVTITCRASQGIRNALGWYQQKPGKAPKRLIYA ASSLQSGVPSRFSGSGSGTEFTLTISSLQPEDFATYYCLQHNSYPRTFGQ GTKVEIRR (SEQ ID NO: 82) Ab1.51 DIQMTQSPSSLSASVGDRVTITCRASQGIRNDLHWYQQKPGKAPKRLIYA ASSLQSGVPSRFSGSGSGTEFTLTISSLQPEDFATYYCLQHYSYPWTFGQ GTKVEIK (SEQ ID NO: 83) Light Chain Constant Domain Optionally, a light chain constant domain is provided. An exemplary sequence is: RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVD NALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGL SSPVTKSFNRGEC (SEQ ID NO: 84) Leader Sequence

Optionally, a leader sequence is included to facilitate expression of the light chains in cell culture. An exemplary sequence is: MDMRVPAQLLGLLLLWLRGARC (SEQ ID NO: 85)

Heavy Chain Variable Region Amino acid Sequences Ab237 QVQLQESGPGLVKPSQTLSLTCTVSGGSINNNNYYWTWIRQHPGKGLEWI GYIYYSGSTFYNPSLKSRVTISVDTSKTQFSLKLSSVTAADTAVYYCARE DTMTGLDVWGQGTTVTVSS (SEQ ID NO: 86) Ab1.1.2 QVQLVESGGGVVQPGRSLRLSCAASGFTFSSYGMHWVRQAPGKGLEWVAA IWYDGSNKYYADSVKGRFTISRDNSKNMLYLQMNSLRAEDTAVYYCARDL SIFGVVILSDYWGQGTLVTVSS (SEQ ID NO: 87) Ab1.33.1 QVQLQESGPGLVKPSQTLSLTCTVSGGSISGDGHFWSWIRQHPGKGLEWI GYIYYSGSTYYNPSLKSRVTISVDTSKNQFSLKLSSVTAADTAVYYCARL RGGYKFDYWGQGTLVTVSS (SEQ ID NO: 88) Ab1.68.1 QVQLQESGPGLVKPSETLSLTCTVSGDSINNYYWSWIRQPAGKGLEWIGR IFTSGSTNYNPSLKSRVTMSIDTSKNQFSLKLSSVTAADTAVYYCAREGG HYGSSGYLYYYYFGMDVWGQGTTVTVSS (SEQ ID NO: 89) Ab1.78.1 QVQLVESGGGVVQPGRSLRLSCAASGFTFSSYGMHWVRQAPGKGLEWVAA IWYDGSNKYYADSVKGRFTISRDNSKNMLYLQMNSLRAEDTAVYYCARDL SIFGVVILSDYWGQGTLVTVSS (SEQ ID NO: 90) Ab1.119.1 QVQLQESGPGLVKPSQTLSLTCTVSGGSISSGGYYWNWIRQHPGKGLEWI GYIYYSGSTYYNPSLRGRLIISVDTSKNQFSLRLSSVTAADTAVYYCARD GGDSYGRMDVWGQGTTVTVSA (SEQ ID NO: 91) Ab2.69.2 QVQLQQSGPGLVKPSQTLSLTCAISGDSVSSNSVAWNWIRQSPSRGLEWL GRTYYRSKWYNDYAVSVKSRITINPDTSKNQFSLQLNSVTPEDTAVYYCA RGIFVVPAVPRFDYWGQGTLVTVSS (SEQ ID NO: 92) Ab1.58 QVQLQESGPGLVKPSETLSLTCTVSGGSIISHYWSWIRQPPGKGLEWIGY IYYSGSTNYNPSLKSRVTISVDTSKNQFSLKLTSVTAADTAVYYCARDGW SAFDYWGQGTLVTVSS (SEQ ID NO: 93) Ab1.51 QVQLQESGPGLVKPSETLSLTCTVSGGSISSYYWSWIRQPPGKGLEWIGY IYYSGSTNYNPSLKSRVTISVDTSKNQFSLKLSSVTAADTAVYYCARVDY KAFDIWGQGTMVTVSS (SEQ ID NO: 94) Leader Sequence

Optionally, a leader sequence is included to facilitate expression of the heavy chains in cell culture. An exemplary sequence is: MKHLWFFLLLVAAPRWVLS (SEQ ID NO: 95)

Heavy Chain Constant Domain

Optionally, a heavy chain constant domain is provided. In certain embodiment, this sequence consists of the heavy chain constant domain sequence from an IgG1, IgG2, IgG3, IgG4 or IgM. An exemplary sequence is:

(SEQ ID NO: 96) ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEP KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTC LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW QQGNVFSCSVMHEALHNHYTQKSLSLSPGK

Particular embodiments of antigen binding proteins of the present invention comprise one or more amino acid sequences that are identical to the amino acid sequences of one or more of the CDRs and/or FRs (framework regions) illustrated above. In one embodiment, the antigen binding protein comprises a light chain CDR1 sequence illustrated above. In another embodiment, the antigen binding protein comprises a light chain CDR2 sequence illustrated above. In another embodiment, the antigen binding protein comprises a light chain CDR3 sequence illustrated in above. In another embodiment, the antigen binding protein comprises a heavy chain CDR1 sequence illustrated above. In another embodiment, the antigen binding protein comprises a heavy chain CDR2 sequence illustrated above. In another embodiment, the antigen binding protein comprises a heavy chain CDR3 sequence illustrated above. In another embodiment, the antigen binding protein comprises a light chain FR1 sequence illustrated above. In another embodiment, the antigen binding protein comprises a light chain FR2 sequence illustrated above. In another embodiment, the antigen binding protein comprises a light chain FR3 sequence illustrated above. In another embodiment, the antigen binding protein comprises a light chain FR4 sequence illustrated above. In another embodiment, the antigen binding protein comprises a heavy chain FR1 sequence illustrated above. In another embodiment, the antigen binding protein comprises a heavy chain FR2 sequence illustrated above. In another embodiment, the antigen binding protein comprises a heavy chain FR3 sequence illustrated above. In another embodiment, the antigen binding protein comprises a heavy chain FR4 sequence illustrated above.

In another embodiment, at least one of the antigen binding protein's CDR3 sequences differs by no more than 6, 5, 4, 3, 2, 1 or 0 single amino acid addition, substitution, and/or deletion from a CDR3 sequence from the sequences as shown in Tables 2 and 3 above. In another embodiment, the antigen binding protein's light chain CDR3 sequence differs by no more than 6, 5, 4, 3, 2, 1 or 0 single amino acid addition, substitution, and/or deletion from a light chain CDR3 sequence from the sequences as shown above and the antigen binding protein's heavy chain CDR3 sequence differs by no more than 6, 5, 4, 3, 2, 1 or 0 single amino acid addition, substitution, and/or deletion from a heavy chain CDR3 sequence from the sequences as shown above. In another embodiment, the antigen binding protein further comprises 1, 2, 3, 4, or 5 CDR sequences that each independently differs by 6, 5, 4, 3, 2, 1, or 0 single amino acid additions, substitutions, and/or deletions from a CDR sequence of the sequences shown above. In another embodiment, the antigen binding protein comprises the CDRs of the light chain variable region and the CDRs of the heavy chain variable region set forth above. In a further embodiment, the antigen binding protein comprises the CDRs of any one of the antibodies listed above. In one embodiment, the antigen binding protein is a human antibody. In another embodiment, the antigen binding protein is a humanized antibody.

In one embodiment, the antigen binding protein (such as an antibody or antibody fragment) comprises a light chain variable domain comprising a sequence of amino acids that differs from the sequence of a light chain variable domain listed above only at 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0 residues, wherein each such sequence difference is independently either a deletion, insertion, or substitution of one amino acid residue. In another embodiment, the light-chain variable domain comprises a sequence of amino acids that is at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, or 99% identical to the sequence of a light chain variable domain listed above. In another embodiment, the light chain variable domain comprises a sequence of amino acids that is encoded by a nucleotide sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, or 99% identical to the polynucleotide sequence listed above. In another embodiment, the light chain variable domain comprises a sequence of amino acids that is encoded by a polynucleotide that hybridizes under moderately stringent conditions to the complement of a polynucleotide that encodes a light chain variable domain selected from the sequences listed above. In another embodiment, the light chain variable domain comprises a sequence of amino acids that is encoded by a polynucleotide that hybridizes under stringent conditions to the complement of a polynucleotide that encodes a light chain variable domain selected from the group consisting of the sequences listed above.

In another embodiment, the present invention provides an antigen binding protein comprising a heavy chain variable domain comprising a sequence of amino acids that differs from the sequence of a heavy chain variable domain selected from the sequences listed above only at 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0 residue(s), wherein each such sequence difference is independently either a deletion, insertion, or substitution of one amino acid residue. In another embodiment, the heavy chain variable domain comprises a sequence of amino acids that is at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, or 99% identical to the sequence of a heavy chain variable domain selected from the sequences listed above. In another embodiment, the heavy chain variable domain comprises a sequence of amino acids that is encoded by a nucleotide sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, or 99% identical to a nucleotide sequence that encodes a heavy chain variable domain selected from the sequences listed above. In another embodiment, the heavy chain variable domain comprises a sequence of amino acids that is encoded by a polynucleotide that hybridizes under moderately stringent conditions to the complement of a polynucleotide that encodes a heavy chain variable domain selected from the sequences listed above. In another embodiment, the heavy chain variable domain comprises a sequence of amino acids that is encoded by a polynucleotide that hybridizes under stringent conditions to the complement of a polynucleotide that encodes a heavy chain variable domain selected from the sequences listed above.

Antigen binding proteins (e.g., antibodies, antibody fragments, and antibody derivatives) of the invention can comprise any constant region known in the art. The light chain constant region can be, for example, a kappa- or lambda-type light chain constant region, e.g., a human kappa- or lambda-type light chain constant region. The heavy chain constant region can be, for example, an alpha-, delta-, epsilon-, gamma-, or mu-type heavy chain constant regions, e.g., a human alpha-, delta-, epsilon-, gamma-, or mu-type heavy chain constant region. In one embodiment, the light or heavy chain constant region is a fragment, derivative, variant, or mutein of a naturally occurring constant region.

The nucleic acid (DNA) encoding constant heavy and constant light chain domains, and the amino acids sequences of heavy and light chain domains are provided herein below. Lambda variable domains can be fused to lambda constant domains and kappa variable domains can be fused to kappa constant domains.

IgG2 Heavy Constant domain DNA (SEQ ID NO: 186): gctagcaccaagggcccatcggtcttccccctggcgccctgctccaggag cacctccgagagcacagcggccctgggctgcctggtcaaggactacttcc ccgaaccggtgacggtgtcgtggaactcaggcgctctgaccagcggcgtg cacaccttcccagctgtcctacagtcctcaggactctactccctcagcag cgtggtgaccgtgccctccagcaacttcggcacccagacctacacctgca acgtagatcacaagcccagcaacaccaaggtggacaagacagttgagcgc aaatgttgtgtcgagtgcccaccgtgcccagcaccacctgtggcaggacc gtcagtcttcctcttccccccaaaacccaaggacaccctcatgatctccc ggacccctgaggtcacgtgcgtggtggtggacgtgagccacgaagacccc gaggtcagttcaactggtacgtggacggcgtggaggtgcataatgccaag acaaagccacgggaggagcagttcaacagcacgttccgtgtggtcagcgt cctcaccgttgtgcaccaggactggctgaacggcaaggagtacaagtgca aggtctccaacaaaggcctcccagcccccatcgagaaaaccatctccaaa accaaagggcagccccgagaaccacaggtgtacaccctgcccccatcccg ggaggagatgaccaagaaccaggtcagcctgacctgcctggtcaaaggct tctaccccagcgacatcgccgtggagtgggagagcaatgggcagccggag aacaactacaagaccacacctcccatgctggactccgacggctccttctt cctctacagcaagctcaccgtggacaagagcaggtggcagcaggggaacg tcttctcatgctccgtgatgcatgaggctctgcacaaccactacacgcag aagagcctctccctgtctccgggtaaatga IgG2 Heavy Constant domain Protein (SEQ ID NO: 187): ASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGV HTFPAVLQSSGLYSLSSVVTVPSSNFGTQTYTCNVDHKPSNTKVDKTVER KCCVECPPCPAPPVAGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDP EVQFNWYVDGVEVHNAKTKPREEQFNSTFRVVSVLTVVHQDWLNGKEYKC KVSNKGLPAPIEKTISKTKGQPREPQVYTLPPSREEMTKNQVSLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPMLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVMHEALHNHYTQKSLSLSPGK Kappa Light Constant domain DNA (SEQ ID NO: 188): cgtacggtggctgcaccatctgtcttcatcttcccgccatctgatgagca gttgaaatctggaactgcctctgttgtgtgcctgctgaataacttctatc ccagagaggccaaagtacagtggaaggtggataacgccctccaatcgggt aactcccaggagagtgtcacagagcaggacagcaaggacagcacctacag cctcagcagcaccctgacgctgagcaaagcagactacgagaaacacaaag tctacgcctgcgaagtcacccatcagggcctgagctcgcccgtcacaaag agcttcaacaggggagagtgttag Kappa Light Constant domain Protein (SEQ ID NO: 189): RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSG NSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTK SFNRGEC Lambda Light Constant domain DNA (SEQ ID NO: 190): ggccaaccgaaagcggcgccctcggtcactctgttcccgccctcctctga ggagcttcaagccaacaaggccacactggtgtgtctcataagtgacttct acccgggagccgtgacagtggcctggaaggcagatagcagccccgtcaag gcgggagtggagaccaccacaccctccaaacaaagcaacaacaagtacgc ggccagcagctatctgagcctgacgcctgagcagtggaagtcccacagaa gctacagctgccaggtcacgcatgaagggagcaccgtggagaagacagtg gcccctacagaatgttcatag Lambda Light Constant domain Protein (SEQ ID NO: 191): GQPKAAPSVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADSSPVK AGVETTTPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVTHEGSTVEKTV APTECS

The specific binding agents of the present invention, such as the antibodies, antibody fragments, and antibody derivatives of the invention include those comprising, for example, the variable domain combinations provided herein having a desired isotype (for example, IgA, IgG1, IgG2, IgG3, IgG4, IgM, IgE, and IgD) as well as Fab or F(ab′)2 fragments thereof. Moreover, if an IgG4 is desired, it may also be desired to introduce a point mutation in the hinge region as described in Bloom et al., 1997, Protein Science 6:407 (incorporated by reference herein) to alleviate a tendency to form intra-H chain disulfide bonds that can lead to heterogeneity in the IgG4 antibodies.

Additional Useful Sequence Information

The following sequences of the IgG1, IgG2, IgG3, and IgG4 isotypes are used in combination with the variable heavy chain sequences of the antibodies of the present invention to make a specific desired isotype of said antibody:

Human IgG1 (SEQ ID NO: 192) ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEP KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTC LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW QQGNVFSCSVMHEALHNHYTQKSLSLSPGK Human IgG2 (SEQ ID NO: 193) ASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGV HTFPAVLQSSGLYSLSSVVTVPSSNFGTQTYTCNVDHKPSNTKVDKTVER KCCVECPPCPAPPVAGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDP EVQFNWYVDGVEVHNAKTKPREEQFNSTFRVVSVLTVVHQDWLNGKEYKC KVSNKGLPAPIEKTISKTKGQPREPQVYTLPPSREEMTKNQVSLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPMLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVMHEALHNHYTQKSLSLSPGK Human IgG3 (SEQ ID NO: 194) ASTKGPSVFPLAPCSRSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYTCNVNHKPSNTKVDKRVEL KTPLGDTTHTCPRCPEPKSCDTPPPCPRCPEPKSCDTPPPCPRCPEPKSC DTPPPCPRCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHED PEVQFKWYVDGVEVHNAKTKPREEQYNSTFRVVSVLTVLHQDWLNGKEYK CKVSNKALPAPIEKTISKTKGQPREPQVYTLPPSREEMTKNQVSLTCLVK GFYPSDIAVEWESSGQPENNYNTTPPMLDSDGSFFLYSKLTVDKSRWQQG NIFSCSVMHEALHNRFTQKSLSLSPGK Human IgG4 (SEQ ID NO: 195) ASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGV HTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNTKVDKRVES KYGPPCPSCPAPEFEGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQED PEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYK CKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEG NVFSCSVMHEALHNHYTQKSLSLSLGK

Techniques are known for deriving an antibody of a different subclass or isotype from an antibody of interest, i.e., subclass switching. Thus, IgG antibodies may be derived from an IgM antibody, for example, and vice versa. Such techniques allow the preparation of new antibodies that possess the antigen-binding properties of a given antibody (the parent antibody), but also exhibit biological properties associated with an antibody isotype or subclass different from that of the parent antibody. Recombinant DNA techniques may be employed. Cloned DNA encoding particular antibody polypeptides may be employed in such procedures, e.g., DNA encoding the constant domain of an antibody of the desired isotype. See also Lanitto et al., Methods Mol. Biol. 178:303-16 (2002).

In one embodiment, an antigen binding protein of the invention further comprises the constant light chain kappa or lambda domains or a fragment of these. Sequences of the light chain constant regions and polynucleotides encoding them are well known in the art. In another embodiment, an antigen binding protein of the invention further comprises a heavy chain constant domain, or a fragment thereof, such as the IgG1 or IgG2 heavy chain constant region, the sequences of which are well known in the art.

The antigen binding proteins (for example, antibodies) of the present invention include those having a desired isotype (for example, IgA, IgG1, IgG2, IgG3, IgG4, IgM, IgE, and IgD) as well as Fab or F(ab′)₂ fragments thereof. Moreover, if an IgG4 is desired, it may also be desired to introduce a point mutation in the hinge region as described in Bloom et al., 1997, Protein Science 6:407, (incorporated by reference herein) to alleviate a tendency to form intra-H chain disulfide bonds that can lead to heterogeneity in the IgG4 antibodies.

Antibodies and Antibody Fragments

In one embodiment the antigen binding proteins are antibodies. The term “antibody” refers to an intact antibody, or an antigen binding fragment thereof, as described extensively in the definition section. An antibody may comprise a complete antibody molecule (including polyclonal, monoclonal, chimeric, humanized, or human versions having full length heavy and/or light chains), or comprise an antigen binding fragment thereof. Antibody fragments include F(ab′)₂, Fab, Fab′, Fv, Fc, and Fd fragments, and can be incorporated into single domain antibodies, single-chain antibodies, maxibodies, minibodies, intrabodies, diabodies, triabodies, tetrabodies, v-NAR and bis-scFv (see e.g., Hollinger and Hudson, 2005, Nature Biotechnology, 23, 9, 1126-1136). Also included are antibody polypeptides such as those disclosed in U.S. Pat. No. 6,703,199, including fibronectin polypeptide monobodies. Other antibody polypeptides are disclosed in U.S. Patent Publication 2005/0238646, which are single-chain polypeptides. In one embodiment, the antibodies of the present invention comprise at least one CDR set forth in Table 2 above. In another aspect, the present invention provides hybridomas capable of producing the antibodies of the invention, and methods of producing antibodies from hybridomas, as described further below.

Chimeric antibodies and humanized antibodies are defined in the definition section and may be prepared by known techniques. In one embodiment, a humanized monoclonal antibody comprises the variable domain of a murine antibody (or all or part of the antigen binding site thereof) and a constant domain derived from a human antibody. Alternatively, a humanized antibody fragment may comprise the antigen binding site of a murine monoclonal antibody and a variable domain fragment (lacking the antigen-binding site) derived from a human antibody. Procedures for the production of engineered monoclonal antibodies include those described in Riechmann et al., 1988, Nature 332:323, Liu et al., 1987, Proc. Nat. Acad. Sci. USA 84:3439, Larrick et al., 1989, Bio/Technology 7:934, and Winter et al., 1993, TIPS 14:139. In one embodiment, the chimeric antibody is a CDR grafted antibody. Techniques for humanizing antibodies are discussed in, e.g., U.S. Pat. Nos. 5,869,619; 5,225,539; 5,821,337; 5,859,205; 6,881,557, Padlan et al., 1995, FASEB J. 9:133-39, Tamura et al., 2000, J. Immunol. 164:1432-41, Zhang, W., et al., Molecular Immunology. 42(12):1445-1451, 2005; Hwang W. et al., Methods. 36(1):35-42, 2005; Dall'Acqua W F, et al., Methods 36(1):43-60, 2005; and Clark, M., Immunology Today. 21(8):397-402, 2000.

An antibody of the present invention may also be a fully human monoclonal antibody. Fully human monoclonal antibodies may be generated by any number of techniques with which those having ordinary skill in the art will be familiar Such methods include, but are not limited to, Epstein Barr Virus (EBV) transformation of human peripheral blood cells (e.g., containing B lymphocytes), in vitro immunization of human B-cells, fusion of spleen cells from immunized transgenic mice carrying inserted human immunoglobulin genes, isolation from human immunoglobulin V region phage libraries, or other procedures as known in the art and based on the disclosure herein.

Procedures have been developed for generating human monoclonal antibodies in non-human animals. For example, mice in which one or more endogenous immunoglobulin genes have been inactivated by various means have been prepared. Human immunoglobulin genes have been introduced into the mice to replace the inactivated mouse genes. In this technique, elements of the human heavy and light chain locus are introduced into strains of mice derived from embryonic stem cell lines that contain targeted disruptions of the endogenous heavy chain and light chain loci (see also Bruggemann et al., Curr. Opin. Biotechnol. 8:455-58 (1997)). For example, human immunoglobulin transgenes may be mini-gene constructs, or transloci on yeast artificial chromosomes, which undergo B-cell-specific DNA rearrangement and hypermutation in the mouse lymphoid tissue.

Antibodies produced in the animal incorporate human immunoglobulin polypeptide chains encoded by the human genetic material introduced into the animal. In one embodiment, a non-human animal, such as a transgenic mouse, is immunized with a suitable mesothelin immunogen.

Examples of techniques for production and use of transgenic animals for the production of human or partially human antibodies are described in U.S. Pat. Nos. 5,814,318, 5,569,825, and 5,545,806, Davis et al., Production of human antibodies from transgenic mice in Lo, ed. Antibody Engineering: Methods and Protocols, Humana Press, NJ:191-200 (2003), Kellermann et al., 2002, Curr Opin Biotechnol. 13:593-97, Russel et al., 2000, Infect Immun 68:1820-26, Gallo et al., 2000, Eur J Immun 30:534-40, Davis et al., 1999, Cancer Metastasis Rev. 18:421-25, Green, 1999, J Immunol Methods. 231:11-23, Jakobovits, 1998, Advanced Drug Delivery Reviews 31:33-42, Green et al., 1998, J Exp Med. 188:483-95, Jakobovits A, 1998, Exp. Opin. Invest. Drugs. 7:607-14, Tsuda et al., 1997, Genomics. 42:413-21, Mendez et al., 1997, Nat Genet. 15:146-56, Jakobovits, 1994, Curr Biol. 4:761-63, Arbones et al., 1994, Immunity. 1:247-60, Green et al., 1994, Nat Genet. 7:13-21, Jakobovits et al., 1993, Nature. 362:255-58, Jakobovits et al., 1993, Proc Natl Acad Sci USA. 90:2551-55. Chen, J., M. Trounstine, F. W. Alt, F. Young, C. Kurahara, J. Loring, D. Huszar “Immunoglobulin gene rearrangement in B-cell deficient mice generated by targeted deletion of the JH locus.” International Immunology 5 (1993): 647-656, Choi et al., 1993, Nature Genetics 4: 117-23, Fishwild et al., 1996, Nature Biotechnology 14: 845-51, Harding et al., 1995, Annals of the New York Academy of Sciences, Lonberg et al., 1994, Nature 368: 856-59, Lonberg, 1994, Transgenic Approaches to Human Monoclonal Antibodies in Handbook of Experimental Pharmacology 113: 49-101, Lonberg et al., 1995, Internal Review of Immunology 13: 65-93, Neuberger, 1996, Nature Biotechnology 14: 826, Taylor et al., 1992, Nucleic Acids Research 20: 6287-95, Taylor et al., 1994, International Immunology 6: 579-91, Tomizuka et al., 1997, Nature Genetics 16: 133-43, Tomizuka et al., 2000, Proceedings of the National Academy of Sciences USA 97: 722-27, Tuaillon et al., 1993, Proceedings of the National Academy of Sciences USA 90: 3720-24, and Tuaillon et al., 1994, Journal of Immunology 152: 2912-20.; Lonberg et al., Nature 368:856, 1994; Taylor et al., Int. Immun 6:579, 1994; U.S. Pat. No. 5,877,397; Bruggemann et al., 1997 Curr. Opin. Biotechnol. 8:455-58; Jakobovits et al., 1995 Ann. N. Y. Acad. Sci. 764:525-35. In addition, protocols involving the XenoMouse® (Abgenix, now Amgen, Inc.) are described, for example in U.S. Ser. No. 05/011,8643 and WO 05/694879, WO 98/24838, WO 00/76310, and U.S. Pat. No. 7,064,244.

Lymphoid cells from the immunized transgenic mice are fused with myeloma cells for example to produce hybridomas. Myeloma cells for use in hybridoma-producing fusion procedures preferably are non-antibody-producing, have high fusion efficiency, and enzyme deficiencies that render them incapable of growing in certain selective media which support the growth of only the desired fused cells (hybridomas). Examples of suitable cell lines for use in such fusions include Sp-20, P3-X63/Ag8, P3-X63-Ag8.653, NS1/1.Ag 4 1, Sp210-Ag14, FO, NSO/U, MPC-11, MPC11-X45-GTG 1.7 and 5194/5XX0 Bul; examples of cell lines used in rat fusions include R210.RCY3, Y3-Ag 1.2.3, IR983F and 4B210. Other cell lines useful for cell fusions are U-266, GM1500-GRG2, LICR-LON-HMy2 and UC729-6.

The lymphoid (e.g., spleen) cells and the myeloma cells may be combined for a few minutes with a membrane fusion-promoting agent, such as polyethylene glycol or a nonionic detergent, and then plated at low density on a selective medium that supports the growth of hybridoma cells but not unfused myeloma cells. One selection media is HAT (hypoxanthine, aminopterin, thymidine). After a sufficient time, usually about one to two weeks, colonies of cells are observed. Single colonies are isolated, and antibodies produced by the cells may be tested for binding activity to mesothelin using any one of a variety of immunoassays known in the art and described herein. The hybridomas are cloned (e.g., by limited dilution cloning or by soft agar plaque isolation) and positive clones that produce an antibody specific to mesothelin are selected and cultured. The monoclonal antibodies from the hybridoma cultures may be isolated from the supernatants of hybridoma cultures. Thus the present invention provides hybridomas that comprise polynucleotides encoding the antigen binding proteins of the invention in the chromosomes of the cell. These hybridomas can be cultured according to methods described herein and known in the art.

Another method for generating human antibodies of the invention includes immortalizing human peripheral blood cells by EBV transformation. See, e.g., U.S. Pat. No. 4,464,456. Such an immortalized B-cell line (or lymphoblastoid cell line) producing a monoclonal antibody that specifically binds to mesothelin can be identified by immunodetection methods as provided herein, for example, an ELISA, and then isolated by standard cloning techniques. The stability of the lymphoblastoid cell line producing an anti-mesothelin antibody may be improved by fusing the transformed cell line with a murine myeloma to produce a mouse-human hybrid cell line according to methods known in the art (see, e.g., Glasky et al., Hybridoma 8:377-89 (1989)). Still another method to generate human monoclonal antibodies is in vitro immunization, which includes priming human splenic B-cells with human mesothelin, followed by fusion of primed B-cells with a heterohybrid fusion partner. See, e.g., Boerner et al., 1991 J. Immunol. 147:86-95.

In certain embodiments, a B-cell that is producing an anti-human mesothelin antibody is selected and the light chain and heavy chain variable regions are cloned from the B-cell according to molecular biology techniques known in the art (WO 92/02551; U.S. Pat. No. 5,627,052; Babcook et al., Proc. Natl. Acad. Sci. USA 93:7843-48 (1996)) and described herein. B-cells from an immunized animal may be isolated from the spleen, lymph node, or peripheral blood sample by selecting a cell that is producing an antibody that specifically binds to mesothelin. B-cells may also be isolated from humans, for example, from a peripheral blood sample. Methods for detecting single B-cells that are producing an antibody with the desired specificity are well known in the art, for example, by plaque formation, fluorescence-activated cell sorting, in vitro stimulation followed by detection of specific antibody, and the like. Methods for selection of specific antibody-producing B-cells include, for example, preparing a single cell suspension of B-cells in soft agar that contains human mesothelin. Binding of the specific antibody produced by the B-cell to the antigen results in the formation of a complex, which may be visible as an immunoprecipitate. After the B-cells producing the desired antibody are selected, the specific antibody genes may be cloned by isolating and amplifying DNA or mRNA according to methods known in the art and described herein.

An additional method for obtaining antibodies of the invention is by phage display. See, e.g., Winter et al., 1994 Annu. Rev. Immunol. 12:433-55; Burton et al., 1994 Adv. Immunol. 57:191-280. Human or murine immunoglobulin variable region gene combinatorial libraries may be created in phage vectors that can be screened to select Ig fragments (Fab, Fv, sFv, or multimers thereof) that bind specifically to TGF-beta binding protein or variant or fragment thereof. See, e.g., U.S. Pat. No. 5,223,409; Huse et al., 1989 Science 246:1275-81; Sastry et al., Proc. Natl. Acad. Sci. USA 86:5728-32 (1989); Alting-Mees et al., Strategies in Molecular Biology 3:1-9 (1990); Kang et al., 1991 Proc. Natl. Acad. Sci. USA 88:4363-66; Hoogenboom et al., 1992 J. Molec. Biol. 227:381-388; Schlebusch et al., 1997 Hybridoma 16:47-52 and references cited therein. For example, a library containing a plurality of polynucleotide sequences encoding Ig variable region fragments may be inserted into the genome of a filamentous bacteriophage, such as M13 or a variant thereof, in frame with the sequence encoding a phage coat protein. A fusion protein may be a fusion of the coat protein with the light chain variable region domain and/or with the heavy chain variable region domain. According to certain embodiments, immunoglobulin Fab fragments may also be displayed on a phage particle (see, e.g., U.S. Pat. No. 5,698,426).

Heavy and light chain immunoglobulin cDNA expression libraries may also be prepared in lambda phage, for example, using λImmunoZap™(H) and λImmunoZap™(L) vectors (Stratagene, La Jolla, Calif.). Briefly, mRNA is isolated from a B-cell population, and used to create heavy and light chain immunoglobulin cDNA expression libraries in the λImmunoZap(H) and λImmunoZap(L) vectors. These vectors may be screened individually or co-expressed to form Fab fragments or antibodies (see Huse et al., supra; see also Sastry et al., supra). Positive plaques may subsequently be converted to a non-lytic plasmid that allows high level expression of monoclonal antibody fragments from E. coli.

In one embodiment, in a hybridoma the variable regions of a gene expressing a monoclonal antibody of interest are amplified using nucleotide primers. These primers may be synthesized by one of ordinary skill in the art, or may be purchased from commercially available sources. (See, e.g., Stratagene (La Jolla, Calif.), which sells primers for mouse and human variable regions including, among others, primers for V_(Ha), V_(Hb), V_(Hc), V_(Hd), C_(H1), V_(L) and C_(L) regions.) These primers may be used to amplify heavy or light chain variable regions, which may then be inserted into vectors such as ImmunoZAP™H or ImmunoZAP™L (Stratagene), respectively. These vectors may then be introduced into E. coli, yeast, or mammalian-based systems for expression. Large amounts of a single-chain protein containing a fusion of the V_(H) and V_(L) domains may be produced using these methods (see Bird et al., Science 242:423-426, 1988).

Once cells producing antibodies according to the invention have been obtained using any of the above-described immunization and other techniques, the specific antibody genes may be cloned by isolating and amplifying DNA or mRNA therefrom according to standard procedures as described herein. The antibodies produced therefrom may be sequenced and the CDRs identified and the DNA coding for the CDRs may be manipulated as described previously to generate other antibodies according to the invention.

In certain embodiments, antibodies are generated by first identifying antibodies that bind to cells expressing mesothelin and/or compete for binding with the antibodies described in this application.

It will be understood by one skilled in the art that some proteins, such as antibodies, may undergo a variety of posttranslational modifications. The type and extent of these modifications often depends on the host cell line used to express the protein as well as the culture conditions. Such modifications may include variations in glycosylation, methionine oxidation, diketopiperizine formation, aspartate isomerization and asparagine deamidation. A frequent modification is the loss of a carboxy-terminal basic residue (such as lysine or arginine) due to the action of carboxypeptidases (as described in Harris, R. J. Journal of Chromatography 705:129-134, 1995).

An alternative method for production of a murine monoclonal antibody is to inject the hybridoma cells into the peritoneal cavity of a syngeneic mouse, for example, a mouse that has been treated (e.g., pristane-primed) to promote formation of ascites fluid containing the monoclonal antibody. Monoclonal antibodies can be isolated and purified by a variety of well-established techniques. Such isolation techniques include affinity chromatography with Protein-A Sepharose, size-exclusion chromatography, and ion-exchange chromatography (see, for example, Coligan at pages 2.7.1-2.7.12 and pages 2.9.1-2.9.3; Baines et al., “Purification of Immunoglobulin G (IgG),” in Methods in Molecular Biology, Vol. 10, pages 79-104 (The Humana Press, Inc. 1992)). Monoclonal antibodies may be purified by affinity chromatography using an appropriate ligand selected based on particular properties of the antibody (e.g., heavy or light chain isotype, binding specificity, etc.). Examples of a suitable ligand, immobilized on a solid support, include Protein A, Protein G, an anticonstant region (light chain or heavy chain) antibody, an anti-idiotype antibody, and a TGF-beta binding protein, or fragment or variant thereof.

Molecular evolution of the complementarity determining regions (CDRs) in the center of the antibody binding site also has been used to isolate antibodies with increased affinity, for example, antibodies having increased affinity for c-erbB-2, as described by Schier et al., 1996, J. Mol. Biol. 263:551. Accordingly, such techniques are useful in preparing antibodies to mesothelin.

Antigen binding proteins directed against mesothelin can be used, for example, in assays to detect the presence of mesothelin, either in vitro or in vivo.

Although human, partially human, or humanized antibodies will be suitable for many applications, particularly those involving administration of the antibody to a human subject, other types of antigen binding proteins will be suitable for certain applications. The non-human antibodies of the invention can be, for example, derived from any antibody-producing animal, such as mouse, rat, rabbit, goat, donkey, or non-human primate (for example, monkey such as cynomologus or rhesus monkey) or ape (e.g., chimpanzee)). Non-human antibodies of the invention can be used, for example, in in vitro and cell-culture based applications, or any other application where an immune response to the antibody of the invention does not occur, is insignificant, can be prevented, is not a concern, or is desired. In one embodiment, a non-human antibody of the invention is administered to a non-human subject. In another embodiment, the non-human antibody does not elicit an immune response in the non-human subject. In another embodiment, the non-human antibody is from the same species as the non-human subject, e.g., a mouse antibody of the invention is administered to a mouse. An antibody from a particular species can be made by, for example, immunizing an animal of that species with the desired immunogen or using an artificial system for generating antibodies of that species (e.g., a bacterial or phage display-based system for generating antibodies of a particular species), or by converting an antibody from one species into an antibody from another species by replacing, e.g., the constant region of the antibody with a constant region from the other species, or by replacing one or more amino acid residues of the antibody so that it more closely resembles the sequence of an antibody from the other species. In one embodiment, the antibody is a chimeric antibody comprising amino acid sequences derived from antibodies from two or more different species.

Antibodies also may be prepared by any of a number of conventional techniques. For example, they may be purified from cells that naturally express them (e.g., an antibody can be purified from a hybridoma that produces it), or produced in recombinant expression systems, using any technique known in the art. See, for example, Monoclonal Antibodies, Hybridomas: A New Dimension in Biological Analyses, Kennet et al. (eds.), Plenum Press, New York (1980); and Antibodies: A Laboratory Manual, Harlow and Land (eds.), Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., (1988). This is discussed in the nucleic acid section below.

Where it is desired to improve the affinity of antibodies according to the invention containing one or more of the above-mentioned CDRs can be obtained by a number of affinity maturation protocols including maintaining the CDRs (Yang et al., J. Mol. Biol., 254, 392-403, 1995), chain shuffling (Marks et al., Bio/Technology, 10, 779-783, 1992), use of mutation strains of E. coli. (Low et al., J. Mol. Biol., 250, 350-368, 1996), DNA shuffling (Patten et al., Curr. Opin. Biotechnol., 8, 724-733, 1997), phage display (Thompson et al., J. Mol. Biol., 256, 7-88, 1996) and additional PCR techniques (Crameri, et al., Nature, 391, 288-291, 1998). All of these methods of affinity maturation are discussed by Vaughan et al. (Nature Biotechnology, 16, 535-539, 1998).

Antibody Fragments

In another aspect, the present invention provides fragments of an anti-mesothelin antibody of the invention. Such fragments can consist entirely of antibody-derived sequences or can comprise additional sequences. Examples of antigen-binding fragments include Fab, F(ab′)2, single chain antibodies, diabodies, triabodies, tetrabodies, and domain antibodies. Other examples are provided in Lunde et al., 2002, Biochem. Soc. Trans. 30:500-06.

Single chain antibodies may be formed by linking heavy and light chain variable domain (Fv region) fragments via an amino acid bridge (short peptide linker), resulting in a single polypeptide chain. Such single-chain Fvs (scFvs) have been prepared by fusing DNA encoding a peptide linker between DNAs encoding the two variable domain polypeptides (V_(L) and V_(H)). The resulting polypeptides can fold back on themselves to form antigen-binding monomers, or they can form multimers (e.g., dimers, trimers, or tetramers), depending on the length of a flexible linker between the two variable domains (Kortt et al., 1997, Prot. Eng. 10:423; Kortt et al., 2001, Biomol. Eng. 18:95-108). By combining different V_(L) and V_(H)-comprising polypeptides, one can form multimeric scFvs that bind to different epitopes (Kriangkum et al., 2001, Biomol. Eng. 18:31-40). Techniques developed for the production of single chain antibodies include those described in U.S. Pat. No. 4,946,778; Bird, 1988, Science 242:423; Huston et al., 1988, Proc. Natl. Acad. Sci. USA 85:5879; Ward et al., 1989, Nature 334:544, de Graaf et al., 2002, Methods Mol Biol. 178:379-87. Single chain antibodies derived from antibodies provided herein include, but are not limited to, scFvs comprising the variable domain combinations L1H1, L2H2, L3H3, L4H4, L5H5, L6H6, L7H7, L8H8, L9H9, and L10H10 are encompassed by the present invention.

Antigen binding fragments derived from an antibody can also be obtained, for example, by proteolytic hydrolysis of the antibody, for example, pepsin or papain digestion of whole antibodies according to conventional methods. By way of example, antibody fragments can be produced by enzymatic cleavage of antibodies with pepsin to provide a 5S fragment termed F(ab′)₂. This fragment can be further cleaved using a thiol reducing agent to produce 3.5S Fab′ monovalent fragments. Optionally, the cleavage reaction can be performed using a blocking group for the sulfhydryl groups that result from cleavage of disulfide linkages. As an alternative, an enzymatic cleavage using papain produces two monovalent Fab fragments and an Fc fragment directly. These methods are described, for example, by Goldenberg, U.S. Pat. No. 4,331,647, Nisonoff et al., Arch. Biochem. Biophys. 89:230, 1960; Porter, Biochem. J. 73:119, 1959; Edelman et al., in Methods in Enzymology 1:422 (Academic Press 1967); and by Andrews, S. M. and Titus, J. A. in Current Protocols in Immunology (Coligan J. E., et al., eds), John Wiley & Sons, New York (2003), pages 2.8.1-2.8.10 and 2.10A.1-2.10A.5. Other methods for cleaving antibodies, such as separating heavy chains to form monovalent light-heavy chain fragments (Fd), further cleaving of fragments, or other enzymatic, chemical, or genetic techniques may also be used, so long as the fragments bind to the antigen that is recognized by the intact antibody.

Another form of an antibody fragment is a peptide comprising one or more complementarity determining regions (CDRs) of an antibody. CDRs can be obtained by constructing polynucleotides that encode the CDR of interest. Such polynucleotides are prepared, for example, by using the polymerase chain reaction to synthesize the variable region using mRNA of antibody-producing cells as a template (see, for example, Larrick et al., Methods: A Companion to Methods in Enzymology 2:106, 1991; Courtenay-Luck, “Genetic Manipulation of Monoclonal Antibodies,” in Monoclonal Antibodies: Production, Engineering and Clinical Application, Ritter et al. (eds.), page 166 (Cambridge University Press 1995); and Ward et al., “Genetic Manipulation and Expression of Antibodies,” in Monoclonal Antibodies: Principles and Applications, Birch et al., (eds.), page 137 (Wiley-Liss, Inc. 1995)). The antibody fragment further may comprise at least one variable region domain of an antibody described herein. Thus, for example, the V region domain may be monomeric and be a V_(H) or V_(L) domain, which is capable of independently binding mesothelin with an affinity at least equal to 10⁻⁷M or less as described below.

The variable region domain may be any naturally occurring variable domain or an engineered version thereof. By engineered version is meant a variable region domain that has been created using recombinant DNA engineering techniques. Such engineered versions include those created, for example, from a specific antibody variable region by insertions, deletions, or changes in or to the amino acid sequences of the specific antibody. Particular examples include engineered variable region domains containing at least one CDR and optionally one or more framework amino acids from a first antibody and the remainder of the variable region domain from a second antibody.

The variable region domain may be covalently attached at a C-terminal amino acid to at least one other antibody domain or a fragment thereof. Thus, for example, a VH domain that is present in the variable region domain may be linked to an immunoglobulin CH1 domain, or a fragment thereof. Similarly a V_(L) domain may be linked to a C_(K) domain or a fragment thereof. In this way, for example, the antibody may be a Fab fragment wherein the antigen binding domain contains associated V_(H) and V_(L) domains covalently linked at their C-termini to a CH1 and C_(K) domain, respectively. The CH1 domain may be extended with further amino acids, for example to provide a hinge region or a portion of a hinge region domain as found in a Fab′ fragment, or to provide further domains, such as antibody CH2 and CH3 domains.

Bispecific Single Chain Antibodies (e.g., Bispecific T-Cell Engagers or BiTEs)

In one embodiment, the invention provides bispecific single chain antibodies, such as, but not limited to, bispecific T-cell engaging molecules (BiTEs). In certain embodiments, the contemplated bispecific single chain antibodies utilize at least two Fv regions to direct binding to target molecules of choice. It is contemplated that two different Fv regions are used, although it is further contemplated that a single Fv region can be used at least twice in a single bispecific single chain antibody. It is contemplated that at least two different target molecules are targeted by the bispecific single chain antibodies of the invention, although it is further contemplated that the same target molecule can be targeted by the at least two Fv regions of the bispecific single chain antibodies.

As is well known, Fv, the minimum antibody fragment which contains a complete antigen recognition and binding site, consists of a dimer of one heavy and one light chain variable domain (VH and VL) in non-covalent association. In this configuration corresponding to the one found in native antibodies, the three CDRs of each variable domain interact to define an antigen binding site on the surface of the VH-VL dimer. Collectively, the six CDRs confer antigen binding specificity to the antibody. Frameworks (FRs) flanking the CDRs have a tertiary structure which is essentially conserved in native immunoglobulins of species as diverse as human and mouse. These FRs serve to hold the CDRs in their appropriate orientation. The constant domains are not required for binding function, but may aid in stabilizing VH-VL interaction.

As used herein, CD3 epsilon denotes a molecule expressed as part of the T cell receptor and has the meaning as typically ascribed to it in the prior art. In human, it encompasses in individual or independently combined form all known CD3 subunits, for example CD3 epsilon, CD3 delta, CD3 gamma, CD3 zeta, CD3 alpha and CD3 beta. The non-chimpanzee primate CD3 antigens as referred to herein are, for example, Macaca fascicularis CD3 and Macaca mulatta CD3. In Macaca fascicularis, it encompasses CD3 epsilon FN-18 negative and CD3 epsilon FN-18 positive, CD3 gamma and CD3 delta. In Macaca mulatta, it encompasses CD3 epsilon, CD3 gamma and CD3 delta. Preferably, said CD3 as used herein is CD3 epsilon. Additional examples of non-chimpanzee primate CD3 molecules are contemplated, for example, cynomolgus CD3.

The human CD3 epsilon is indicated in GenBank Accession No. NM-000733. The human CD3 gamma is indicated in GenBank Accession NO. NM-000073. The human CD3 delta is indicated in GenBank Accession No. NM-000732.

It is also envisaged in the context of the present invention that the bispecific antibody constructs provided in the pharmaceutical composition of the invention are further modified. In particular, it is envisaged that the bispecific single chain antibody construct in the format V_(H)(MSLN)—V_(L)(MSLN)—V_(H)(CD3)-V_(L)(CD3), V_(H)(CD3)-V_(L)(CD3)-V_(H)(MSLN)—V_(L)(MSLN) or V_(H)(CD3)-V_(L)(CD3)-V_(L)(MSLN)—V_(H)(MSLN) as defined herein are deimmunized. In certain embodiments, at least the CD3-binding portion is deimmunized. Deimmunization entails carrying out substitutions of amino acids within potential T cell epitopes.

In certain embodiments, the bispecific single chain antibodies comprise at least one CDR-3 of a VH-region of an antibody directed against human CD3, at least one CDR-3 of a VL-region of an antibody directed against human CD3, at least one CDR-3 of a VH-region of an antibody directed against human MSLN and at least one CDR-3 of a VL-region of an antibody directed against human MSLN. In further embodiments, the bispecific single chain antibodies comprise VH and VL regions which comprise not only CDR-3 but also CDR1 and/or CDR2 regions. In particular, CDR-regions (e.g., CDRs 1-3 of the VH and VL) may be employed to generate further bispecific single chain constructs. In further embodiments, the bispecific single chain antibodies are derived from the parental antibodies as disclosed herein and share, as disclosed above, at least the CDR-3 domain of the VH-region and the CDR-3 domain of the VL-region with said parental antibodies, and in certain embodiments share CDRs 1-3 of the VH and VL regions of said parental antibodies. It is also envisaged that the bispecific single chain antibodies further comprise modified CDR regions. It is, e.g., envisaged that in particular CDR2 and/or CDR1 regions (or frameworks or linkers between CDRs) are deimmunized. For futher disclosure relating to bispecific single chain antibodies, see, for example, U.S. Pat. Nos. 6,723,538; 7,112,324; 7,227,002; 7,235,641; 7,323,440; 7,332,168; 7,635,472; 7,820,166; 7,919,089; 8,017,748; 8,076,459; 8,101,722; 8,236,308; and 8,247,194. See also, for example, U.S. Patent Publication Nos. 20090241202, 20090291072, 20100150918 (WO 2008/119567), 20110262439, 20110293619, 20120034228, and 20120244162.

In one embodiment, the VH and VL regions of said CD3 specific domain are derived from a CD3 specific antibody selected from the group consisting of X35-3, VIT3, BMA030 (BW264/56), CLB-T3/3, CRIS7, YTH12.5, F111-409, CLB-T3.4.2, WT31, WT32, SPv-T3b, 11D8, XIII-141, XIII-46, XIII-87, 12F6, T3/RW2-8C8, T3/RW2-4B6, OKT3D, M-T301, SMC2 and F101.01. These CD3-specific antibodies are well known in the art and described in Tunnacliffe (1989), Int. Immunol. 1, 546-550. In another embodiment, said VH and VL regions of said CD3 specific domain are derived from OKT3 (as described above). In a further embodiment, said VH and VL regions are or are derived from an antibody/antibody derivative specifically directed against CD3 described by Traunecker (1991), EMBO J. 10, 3655-3659. In a further embodiment, said VH and VL regions are or are derived from an antibody/antibody derivative specifically directed against CD3 described in U.S. Patent Publication No. 20100150918 (WO 2008/119567). In a specific embodiment, said VH and VL regions are or are derived from an antibody/antibody I2C as described in U.S. Patent Publication No. 20100150918 (WO 2008/119567).

In accordance with this invention, said VH and VL regions are derived from antibodies/antibody derivatives and the like which are capable of specifically recognizing human CD3 epsilon in the context of other TCR subunits, e.g. in mouse T cells transgenic for human CD3 epsilon. These transgenic mouse cells express human CD3 epsilon in a native or near native conformation. Accordingly, the VH and VL regions derived from a CD3-epsilon-specific antibody are envisioned as further embodiments in accordance with this invention and said (parental) antibodies should be capable of specifically binding epitopes reflecting the native or near native structure or a conformational epitope of human CD3 presented in context of the TCR complex. Such antibodies have been classified by Tunnacliffe (1989) as “group II” antibodies.

Further classifications in Tunnacliffe (1989) comprise the definition of “group I” and “group III” antibodies directed against CD3. “Group I” antibodies, like UCHT1, recognize CD3 epsilon both expressed as recombinant protein as well as part of the TCR on the cell surface. Therefore, “group I” antibodies are highly specific for CD3 epsilon. In contrast, the herein preferred “group II” antibodies recognize CD3 epsilon only in the native TCR complex in association with other TCR subunits. Without being bound by theory, it is speculated in context of this invention that in “group II” antibodies, the TCR context is required for recognition of CD3 epsilon. CD3 gamma and/or delta, being associated with epsilon, are also involved in binding of “group II” antibodies. All three subunits express immuno-tyrosine activation motifs (ITAMs) which can be tyrosine phosphorylated by protein tyrosine kinases. For this reason “group II” antibodies induce T cell signaling via CD3 epsilon, gamma and delta, leading to a stronger signal compared to “group I” antibodies selectively inducing T cell signaling via CD3 epsilon. Yet, since for therapeutic applications induction of a strong T cell signaling is desired, the VH(CD3)/VL (CD3)-regions (or parts thereof) to be employed in the bispecific single chain constructs comprised in the inventive pharmaceutical composition, are derived from antibodies directed against human CD3 and classified as “group II” by Tunnacliffe (1989).

Derivatives and Variants of Antigen Binding Proteins

The nucleotide sequences of the antibodies of the present invention, encoding the corresponding amino acid sequences of the antibodies of the present invention, can be altered, for example, by random mutagenesis or by site-directed mutagenesis (e.g., oligonucleotide-directed site-specific mutagenesis) to create an altered polynucleotide comprising one or more particular nucleotide substitutions, deletions, or insertions as compared to the non-mutated polynucleotide. Examples of techniques for making such alterations are described in Walder et al., 1986, Gene 42:133; Bauer et al. 1985, Gene 37:73; Craik, BioTechniques, January 1985, 12-19; Smith et al., 1981, Genetic Engineering: Principles and Methods, Plenum Press; and U.S. Pat. Nos. 4,518,584 and 4,737,462. These and other methods can be used to make, for example, derivatives of anti-mesothelin antibodies that have a desired property, for example, increased affinity, avidity, or specificity for mesothelin increased activity or stability in vivo or in vitro, or reduced in vivo side-effects as compared to the underivatized antibody.

Other derivatives of anti-mesothelin antibodies within the scope of this invention include covalent or aggregative conjugates of anti-mesothelin antibodies, or fragments thereof, with other proteins or polypeptides, such as by expression of recombinant fusion proteins comprising heterologous polypeptides fused to the N-terminus or C-terminus of an anti-mesothelin antibody polypeptide. For example, the conjugated peptide may be a heterologous signal (or leader) polypeptide, e.g., the yeast alpha-factor leader, or a peptide such as an epitope tag. Antigen binding protein-containing fusion proteins can comprise peptides added to facilitate purification or identification of antigen binding protein (e.g., poly-His). An antigen binding protein also can be linked to the FLAG peptide as described in Hopp et al., Bio/Technology 6:1204, 1988, and U.S. Pat. No. 5,011,912. The FLAG peptide is highly antigenic and provides an epitope reversibly bound by a specific monoclonal antibody (mAb), enabling rapid assay and facile purification of expressed recombinant protein. Reagents useful for preparing fusion proteins in which the FLAG peptide is fused to a given polypeptide are commercially available (Sigma, St. Louis, Mo.).

In another embodiment, oligomers that contain one or more antigen binding proteins may be employed as mesothelin antagonists. Oligomers may be in the form of covalently-linked or non-covalently-linked dimers, trimers, or higher oligomers. Oligomers comprising two or more antigen binding protein are contemplated for use, with one example being a homodimer. Other oligomers include heterodimers, homotrimers, heterotrimers, homotetramers, heterotetramers, etc.

One embodiment is directed to oligomers comprising multiple antigen binding proteins joined via covalent or non-covalent interactions between peptide moieties fused to the antigen binding proteins. Such peptides may be peptide linkers (spacers), or peptides that have the property of promoting oligomerization. Leucine zippers and certain polypeptides derived from antibodies are among the peptides that can promote oligomerization of antigen binding proteins attached thereto, as described in more detail below.

In particular embodiments, the oligomers comprise from two to four antigen binding proteins. The antigen binding proteins of the oligomer may be in any form, such as any of the forms described above, e.g., variants or fragments. Preferably, the oligomers comprise antigen binding proteins that have mesothelin binding activity.

In one embodiment, an oligomer is prepared using polypeptides derived from immunoglobulins. Preparation of fusion proteins comprising certain heterologous polypeptides fused to various portions of antibody-derived polypeptides (including the Fc domain) has been described, e.g., by Ashkenazi et al., 1991, PNAS USA 88:10535; Byrn et al., 1990, Nature 344:677; and Hollenbaugh et al., 1992 “Construction of Immunoglobulin Fusion Proteins”, in Current Protocols in Immunology, Suppl. 4, pages 10.19.1-10.19.11. One embodiment of the present invention is directed to a dimer comprising two fusion proteins created by fusing a mesothelin binding fragment of an anti-mesothelin antibody to the Fc region of an antibody. The dimer can be made by, for example, inserting a gene fusion encoding the fusion protein into an appropriate expression vector, expressing the gene fusion in host cells transformed with the recombinant expression vector, and allowing the expressed fusion protein to assemble much like antibody molecules, whereupon interchain disulfide bonds form between the Fc moieties to yield the dimer.

The term “Fc polypeptide” as used herein includes native and mutein forms of polypeptides derived from the Fc region of an antibody. Truncated forms of such polypeptides containing the hinge region that promotes dimerization also are included. Fusion proteins comprising Fc moieties (and oligomers formed therefrom) offer the advantage of facile purification by affinity chromatography over Protein A or Protein G columns.

One suitable Fc polypeptide, described in PCT application WO 93/10151 (hereby incorporated by reference), is a single chain polypeptide extending from the N-terminal hinge region to the native C-terminus of the Fc region of a human IgG1 antibody. Another useful Fc polypeptide is the Fc mutein described in U.S. Pat. No. 5,457,035 and in Baum et al., 1994, EMBO J. 13:3992-4001. The amino acid sequence of this mutein is identical to that of the native Fc sequence presented in WO 93/10151, except that amino acid 19 has been changed from Leu to Ala, amino acid 20 has been changed from Leu to Glu, and amino acid 22 has been changed from Gly to Ala. The mutein exhibits reduced affinity for Fc receptors. In other embodiments, the variable portion of the heavy and/or light chains of an anti-mesothelin antibody may be substituted for the variable portion of an antibody heavy and/or light chain.

Alternatively, the oligomer is a fusion protein comprising multiple antigen binding proteins, with or without peptide linkers (spacer peptides). Among the suitable peptide linkers are those described in U.S. Pat. Nos. 4,751,180 and 4,935,233.

Another method for preparing oligomeric antigen binding proteins involves use of a leucine zipper. Leucine zipper domains are peptides that promote oligomerization of the proteins in which they are found. Leucine zippers were originally identified in several DNA-binding proteins (Landschulz et al., 1988, Science 240:1759), and have since been found in a variety of different proteins. Among the known leucine zippers are naturally occurring peptides and derivatives thereof that dimerize or trimerize. Examples of leucine zipper domains suitable for producing soluble oligomeric proteins are described in PCT application WO 94/10308, and the leucine zipper derived from lung surfactant protein D (SPD) described in Hoppe et al., 1994, FEBS Letters 344:191, hereby incorporated by reference. The use of a modified leucine zipper that allows for stable trimerization of a heterologous protein fused thereto is described in Fanslow et al., 1994, Semin. Immunol. 6:267-78. In one approach, recombinant fusion proteins comprising an anti-mesothelin antibody fragment or derivative fused to a leucine zipper peptide are expressed in suitable host cells, and the soluble oligomeric anti-mesothelin antibody fragments or derivatives that form are recovered from the culture supernatant.

In another embodiment, the antibody derivatives can comprise at least one of the CDRs disclosed herein. For example, one or more CDR may be incorporated into known antibody framework regions (IgG1, IgG2, etc.), or conjugated to a suitable vehicle to enhance the half-life thereof. Suitable vehicles include, but are not limited to Fc, albumin, transferrin, and the like. These and other suitable vehicles are known in the art. Such conjugated CDR peptides may be in monomeric, dimeric, tetrameric, or other form. In one embodiment, one or more water-soluble polymer is bonded at one or more specific position, for example at the amino terminus, of a binding agent. In an example, an antibody derivative comprises one or more water soluble polymer attachments, including, but not limited to, polyethylene glycol, polyoxyethylene glycol, or polypropylene glycol. See, e.g., U.S. Pat. Nos. 4,640,835, 4,496,689, 4,301,144, 4,670,417, 4,791,192 and 4,179,337. In certain embodiments, a derivative comprises one or more of monomethoxy-polyethylene glycol, dextran, cellulose, or other carbohydrate based polymers, poly-(N-vinyl pyrrolidone)-polyethylene glycol, propylene glycol homopolymers, a polypropylene oxide/ethylene oxide co-polymer, polyoxyethylated polyols (e.g., glycerol) and polyvinyl alcohol, as well as mixtures of such polymers. In certain embodiments, one or more water-soluble polymer is randomly attached to one or more side chains. In certain embodiments, PEG can act to improve the therapeutic capacity for a binding agent, such as an antibody. Certain such methods are discussed, for example, in U.S. Pat. No. 6,133,426, which is hereby incorporated by reference for any purpose.

It will be appreciated that an antigen binding protein or antibody of the present invention may have at least one amino acid substitution, providing that the antigen binding protein or antibody retains binding specificity. Therefore, modifications to the antigen binding protein or antibody structures are encompassed within the scope of the invention. These may include amino acid substitutions, which may be conservative or non-conservative, that do not destroy the mesothelin binding capability of an antigen binding protein or antibody. Conservative amino acid substitutions may encompass non-naturally occurring amino acid residues, which are typically incorporated by chemical peptide synthesis rather than by synthesis in biological systems. These include peptidomimetics and other reversed or inverted forms of amino acid moieties. A conservative amino acid substitution may also involve a substitution of a native amino acid residue with a normative residue such that there is little or no effect on the polarity or charge of the amino acid residue at that position. Non-conservative substitutions may involve the exchange of a member of one class of amino acids or amino acid mimetics for a member from another class with different physical properties (e.g. size, polarity, hydrophobicity, charge). For example, such substituted residues may be introduced into regions of the human antibody that are homologous with non-human antibodies, or into the non-homologous regions of the molecule.

In certain embodiments, an amino acid substitution is made to improve protein expression, or to improve upon protein stability. For example, but not limited to, in one embodiment, the glutamine (Gln, Q) at the amino terminus of a variable heavy and/or a variable light chain of a binding protein is substituted with glutamic acid (Glu, E).

Moreover, one skilled in the art may generate test variants containing a single amino acid substitution at each desired amino acid residue. The variants can then be screened using activity assays known to those skilled in the art. Such variants could be used to gather information about suitable variants. For example, if one discovered that a change to a particular amino acid residue resulted in destroyed, undesirably reduced, or unsuitable activity, variants with such a change may be avoided. In other words, based on information gathered from such routine experiments, one skilled in the art can readily determine the amino acids where further substitutions should be avoided either alone or in combination with other mutations.

A skilled artisan will be able to determine suitable variants of the polypeptide as set forth herein using well-known techniques. In certain embodiments, one skilled in the art may identify suitable areas of the molecule that may be changed without destroying activity by targeting regions not believed to be important for activity. In certain embodiments, one can identify residues and portions of the molecules that are conserved among similar polypeptides. In certain embodiments, even areas that may be important for biological activity or for structure may be subject to conservative amino acid substitutions without destroying the biological activity or without adversely affecting the polypeptide structure. Additionally, one skilled in the art can review structure-function studies identifying residues in similar polypeptides that are important for activity or structure. In view of such a comparison, one can predict the importance of amino acid residues in a protein that correspond to amino acid residues which are important for activity or structure in similar proteins. One skilled in the art may opt for chemically similar amino acid substitutions for such predicted important amino acid residues.

One skilled in the art can also analyze the three-dimensional structure and amino acid sequence in relation to that structure in similar polypeptides. In view of such information, one skilled in the art may predict the alignment of amino acid residues of an antibody with respect to its three dimensional structure. In certain embodiments, one skilled in the art may choose not to make radical changes to amino acid residues predicted to be on the surface of the protein, since such residues may be involved in important interactions with other molecules. A number of scientific publications have been devoted to the prediction of secondary structure. See Moult J., Curr. Op. in Biotech., 7(4):422-427 (1996), Chou et al., Biochemistry, 13(2):222-245 (1974); Chou et al., Biochemistry, 113(2):211-222 (1974); Chou et al., Adv. Enzymol. Relat. Areas Mol. Biol., 47:45-148 (1978); Chou et al., Ann. Rev. Biochem., 47:251-276 and Chou et al., Biophys. J., 26:367-384 (1979). Moreover, computer programs are currently available to assist with predicting secondary structure. One method of predicting secondary structure is based upon homology modeling. For example, two polypeptides or proteins which have a sequence identity of greater than 30%, or similarity greater than 40% often have similar structural topologies. The recent growth of the protein structural database (PDB) has provided enhanced predictability of secondary structure, including the potential number of folds within a polypeptide's or protein's structure. See Holm et al., Nucl. Acid. Res., 27(1):244-247 (1999). It has been suggested (Brenner et al., Curr. Op. Struct. Biol., 7(3):369-376 (1997)) that there are a limited number of folds in a given polypeptide or protein and that once a critical number of structures have been resolved, structural prediction will become dramatically more accurate.

Additional methods of predicting secondary structure include “threading” (Jones, D., Curr. Opin. Struct. Biol., 7(3):377-87 (1997); Sippl et al., Structure, 4(1):15-19 (1996)), “profile analysis” (Bowie et al., Science, 253:164-170 (1991); Gribskov et al., Meth. Enzym., 183:146-159 (1990); Gribskov et al., Proc. Nat. Acad. Sci., 84(13):4355-4358 (1987)), and “evolutionary linkage” (See Holm, supra (1999), and Brenner, supra (1997)). In certain embodiments, variants of antibodies include glycosylation variants wherein the number and/or type of glycosylation site has been altered compared to the amino acid sequences of a parent polypeptide. In certain embodiments, variants comprise a greater or a lesser number of N-linked glycosylation sites than the native protein. Alternatively, substitutions which eliminate this sequence will remove an existing N-linked carbohydrate chain. Also provided is a rearrangement of N-linked carbohydrate chains wherein one or more N-linked glycosylation sites (typically those that are naturally occurring) are eliminated and one or more new N-linked sites are created. Additional antibody variants include cysteine variants wherein one or more cysteine residues are deleted from or substituted for another amino acid (e.g., serine) as compared to the parent amino acid sequence. Cysteine variants may be useful when antibodies must be refolded into a biologically active conformation such as after the isolation of insoluble inclusion bodies. Cysteine variants generally have fewer cysteine residues than the native protein, and typically have an even number to minimize interactions resulting from unpaired cysteines.

Desired amino acid substitutions (whether conservative or non-conservative) can be determined by those skilled in the art at the time such substitutions are desired. In certain embodiments, amino acid substitutions can be used to identify important residues of antibodies to mesothelin, or to increase or decrease the affinity of the antibodies to mesothelin described herein.

According to certain embodiments, preferred amino acid substitutions are those which: (1) reduce susceptibility to proteolysis, (2) reduce susceptibility to oxidation, (3) alter binding affinity for forming protein complexes, (4) alter binding affinities, and/or (4) confer or modify other physiochemical or functional properties on such polypeptides. According to certain embodiments, single or multiple amino acid substitutions (in certain embodiments, conservative amino acid substitutions) may be made in the naturally-occurring sequence (in certain embodiments, in the portion of the polypeptide outside the domain(s) forming intermolecular contacts). In certain embodiments, a conservative amino acid substitution typically may not substantially change the structural characteristics of the parent sequence (e.g., a replacement amino acid should not tend to break a helix that occurs in the parent sequence, or disrupt other types of secondary structure that characterizes the parent sequence). Examples of art-recognized polypeptide secondary and tertiary structures are described in Proteins, Structures and Molecular Principles (Creighton, Ed., W. H. Freeman and Company, New York (1984)); Introduction to Protein Structure (C. Branden and J. Tooze, eds., Garland Publishing, New York, N.Y. (1991)); and Thornton et al. Nature 354:105 (1991), which are each incorporated herein by reference.

In certain embodiments, antibodies of the invention may be chemically bonded with polymers, lipids, or other moieties.

The antigen binding proteins may comprise at least one of the CDRs described herein incorporated into a biocompatible framework structure. In one example, the biocompatible framework structure comprises a polypeptide or portion thereof that is sufficient to form a conformationally stable structural support, or framework, or scaffold, which is able to display one or more sequences of amino acids that bind to an antigen (e.g., CDRs, a variable region, etc.) in a localized surface region. Such structures can be a naturally occurring polypeptide or polypeptide “fold” (a structural motif), or can have one or more modifications, such as additions, deletions or substitutions of amino acids, relative to a naturally occurring polypeptide or fold. These scaffolds can be derived from a polypeptide of any species (or of more than one species), such as a human, other mammal, other vertebrate, invertebrate, plant, bacteria or virus.

Typically the biocompatible framework structures are based on protein scaffolds or skeletons other than immunoglobulin domains. For example, those based on fibronectin, ankyrin, lipocalin, neocarzinostain, cytochrome b, CP1 zinc finger, PST1, coiled coil, LACI-D1, Z domain and tendamistat domains may be used (See e.g., Nygren and Uhlen, 1997, Current Opinion in Structural Biology, 7, 463-469).

Additionally, one skilled in the art will recognize that suitable binding agents include portions of these antibodies, such as one or more of heavy chain CDR1, CDR2, CDR3, light chain CDR1, CDR2 and CDR3 as specifically disclosed herein. At least one of the regions of heavy chain CDR1, CDR2, CDR3, CDR1, CDR2 and CDR3 may have at least one amino acid substitution, provided that the antibody or antigen binding protein retains the binding specificity of the non-substituted CDR. The non-CDR portion of the antibody or antigen binding protein may be a non-protein molecule. The non-CDR portion of the antibody or antigen binding protein may be composed of amino acids, wherein the antibody or antigen binding protein is a recombinant binding protein or a synthetic peptide.

Nucleic Acids

In one aspect, the present invention provides isolated nucleic acid molecules that encode the antigen binding proteins of the present invention. In addition, provided are vectors comprising the nucleic acids, cell comprising the nucleic acids, and methods of making the antigen binding proteins of the invention. The nucleic acids comprise, for example, polynucleotides that encode all or part of an antigen binding protein, for example, one or both chains of an antibody of the invention, or a fragment, derivative, mutein, or variant thereof, polynucleotides sufficient for use as hybridization probes, PCR primers or sequencing primers for identifying, analyzing, mutating or amplifying a polynucleotide encoding a polypeptide, anti-sense nucleic acids for inhibiting expression of a polynucleotide, and complementary sequences of the foregoing. The nucleic acids can be any length. They can be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 750, 1,000, 1,500, 3,000, 5,000 or more nucleotides in length, and/or can comprise one or more additional sequences, for example, regulatory sequences, and/or be part of a larger nucleic acid, for example, a vector. The nucleic acids can be single-stranded or double-stranded and can comprise RNA and/or DNA nucleotides, and artificial variants thereof (e.g., peptide nucleic acids).

Nucleic acids encoding antibody polypeptides (e.g., heavy or light chain, variable domain only, or full length) may be isolated from B-cells of mice that have been immunized with mesothelin antigen. The nucleic acid may be isolated by conventional procedures such as polymerase chain reaction (PCR).

Nucleic acid sequences encoding the variable regions of the heavy and light chain variable regions are shown above. The skilled artisan will appreciate that, due to the degeneracy of the genetic code, each of the polypeptide sequences disclosed herein is encoded by a large number of other nucleic acid sequences. The present invention provides each degenerate nucleotide sequence encoding each antigen binding protein of the invention.

The invention further provides nucleic acids that hybridize to other nucleic acids (e.g., nucleic acids comprising a nucleotide sequence of any of A1-A14) under particular hybridization conditions. Methods for hybridizing nucleic acids are well-known in the art. See, e.g., Current Protocols in Molecular Biology, John Wiley & Sons, N.Y. (1989), 6.3.1-6.3.6. As defined herein, for example, a moderately stringent hybridization condition uses a prewashing solution containing 5× sodium chloride/sodium citrate (SSC), 0.5% SDS, 1.0 mM EDTA (pH 8.0), hybridization buffer of about 50% formamide, 6×SSC, and a hybridization temperature of 55° C. (or other similar hybridization solutions, such as one containing about 50% formamide, with a hybridization temperature of 42° C.), and washing conditions of 60° C., in 0.5×SSC, 0.1% SDS. A stringent hybridization condition hybridizes in 6×SSC at 45° C., followed by one or more washes in 0.1×SSC, 0.2% SDS at 68° C. Furthermore, one of skill in the art can manipulate the hybridization and/or washing conditions to increase or decrease the stringency of hybridization such that nucleic acids comprising nucleotide sequences that are at least 65, 70, 75, 80, 85, 90, 95, 98 or 99% identical to each other typically remain hybridized to each other. The basic parameters affecting the choice of hybridization conditions and guidance for devising suitable conditions are set forth by, for example, Sambrook, Fritsch, and Maniatis (1989, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., chapters 9 and 11; and Current Protocols in Molecular Biology, 1995, Ausubel et al., eds., John Wiley & Sons, Inc., sections 2.10 and 6.3-6.4), and can be readily determined by those having ordinary skill in the art based on, for example, the length and/or base composition of the DNA. Changes can be introduced by mutation into a nucleic acid, thereby leading to changes in the amino acid sequence of a polypeptide (e.g., an antigen binding protein) that it encodes. Mutations can be introduced using any technique known in the art. In one embodiment, one or more particular amino acid residues are changed using, for example, a site-directed mutagenesis protocol. In another embodiment, one or more randomly selected residues is changed using, for example, a random mutagenesis protocol. However it is made, a mutant polypeptide can be expressed and screened for a desired property.

Mutations can be introduced into a nucleic acid without significantly altering the biological activity of a polypeptide that it encodes. For example, one can make nucleotide substitutions leading to amino acid substitutions at non-essential amino acid residues. In one embodiment, a nucleotide sequence provided herein for of the antibodies of the present invention, or a desired fragment, variant, or derivative thereof, is mutated such that it encodes an amino acid sequence comprising one or more deletions or substitutions of amino acid residues that are shown herein for the light chains of the antibodies of the present invention or the heavy chains of the antibodies of the present invention to be residues where two or more sequences differ. In another embodiment, the mutagenesis inserts an amino acid adjacent to one or more amino acid residues shown herein for the light chains of the antibodies of the present invention or the heavy chains of the antibodies of the present invention to be residues where two or more sequences differ. Alternatively, one or more mutations can be introduced into a nucleic acid that selectively change the biological activity. (e.g., binding to mesothelin) of a polypeptide that it encodes. For example, the mutation can quantitatively or qualitatively change the biological activity. Examples of quantitative changes include increasing, reducing or eliminating the activity. Examples of qualitative changes include changing the antigen specificity of an antigen binding protein.

In another aspect, the present invention provides nucleic acid molecules that are suitable for use as primers or hybridization probes for the detection of nucleic acid sequences of the invention. A nucleic acid molecule of the invention can comprise only a portion of a nucleic acid sequence encoding a full-length polypeptide of the invention, for example, a fragment that can be used as a probe or primer or a fragment encoding an active portion (e.g., a mesothelin binding portion) of a polypeptide of the invention.

Probes based on the sequence of a nucleic acid of the invention can be used to detect the nucleic acid or similar nucleic acids, for example, transcripts encoding a polypeptide of the invention. The probe can comprise a label group, e.g., a radioisotope, a fluorescent compound, an enzyme, or an enzyme co-factor. Such probes can be used to identify a cell that expresses the polypeptide.

In another aspect, the present invention provides vectors comprising a nucleic acid encoding a polypeptide of the invention or a portion thereof. Examples of vectors include, but are not limited to, plasmids, viral vectors, non-episomal mammalian vectors and expression vectors, for example, recombinant expression vectors.

The recombinant expression vectors of the invention can comprise a nucleic acid of the invention in a form suitable for expression of the nucleic acid in a host cell. The recombinant expression vectors include one or more regulatory sequences, selected on the basis of the host cells to be used for expression, which is operably linked to the nucleic acid sequence to be expressed. Regulatory sequences include those that direct constitutive expression of a nucleotide sequence in many types of host cells (e.g., SV40 early gene enhancer, Rous sarcoma virus promoter and cytomegalovirus promoter), those that direct expression of the nucleotide sequence only in certain host cells (e.g., tissue-specific regulatory sequences, see Voss et al., 1986, Trends Biochem. Sci. 11:287, Maniatis et al., 1987, Science 236:1237, incorporated by reference herein in their entireties), and those that direct inducible expression of a nucleotide sequence in response to particular treatment or condition (e.g., the metallothionin promoter in mammalian cells and the tet-responsive and/or streptomycin responsive promoter in both prokaryotic and eukaryotic systems (see id.). It will be appreciated by those skilled in the art that the design of the expression vector can depend on such factors as the choice of the host cell to be transformed, the level of expression of protein desired, etc. The expression vectors of the invention can be introduced into host cells to thereby produce proteins or peptides, including fusion proteins or peptides, encoded by nucleic acids as described herein.

In another aspect, the present invention provides host cells into which a recombinant expression vector of the invention has been introduced. A host cell can be any prokaryotic cell or eukaryotic cell. Prokaryotic host cells include gram negative or gram positive organisms, for example E. coli or bacilli. Higher eukaryotic cells include insect cells, yeast cells, and established cell lines of mammalian origin. Examples of suitable mammalian host cell lines include Chinese hamster ovary (CHO) cells or their derivatives such as Veggie CHO and related cell lines which grow in serum-free media (see Rasmussen et al., 1998, Cytotechnology 28:31) or CHO strain DXB-11, which is deficient in DHFR (see Urlaub et al., 1980, Proc. Natl. Acad. Sci. USA 77:4216-20). Additional CHO cell lines include CHO—K1 (ATCC #CCL-61), EM9 (ATCC #CRL-1861), and UV20 (ATCC #CRL-1862). Additional host cells include the COS-7 line of monkey kidney cells (ATCC CRL 1651) (see Gluzman et al., 1981, Cell 23:175), L cells, C127 cells, 3T3 cells (ATCC CCL 163), AM-1/D cells (described in U.S. Pat. No. 6,210,924), HeLa cells, BHK (ATCC CRL 10) cell lines, the CV1/EBNA cell line derived from the African green monkey kidney cell line CV1 (ATCC CCL 70) (see McMahan et al., 1991, EMBO J. 10:2821), human embryonic kidney cells such as 293, 293 EBNA or MSR 293, human epidermal A431 cells, human Colo205 cells, other transformed primate cell lines, normal diploid cells, cell strains derived from in vitro culture of primary tissue, primary explants, HL-60, U937, HaK or Jurkat cells. Appropriate cloning and expression vectors for use with bacterial, fungal, yeast, and mammalian cellular hosts are described by Pouwels et al. (Cloning Vectors: A Laboratory Manual, Elsevier, New York, 1985).

Vector DNA can be introduced into prokaryotic or eukaryotic cells via conventional transformation or transfection techniques. For stable transfection of mammalian cells, it is known that, depending upon the expression vector and transfection technique used, only a small fraction of cells may integrate the foreign DNA into their genome. In order to identify and select these integrants, a gene that encodes a selectable marker (e.g., for resistance to antibiotics) is generally introduced into the host cells along with the gene of interest. Additional selectable markers include those which confer resistance to drugs, such as G418, hygromycin and methotrexate. Cells stably transfected with the introduced nucleic acid can be identified by drug selection (e.g., cells that have incorporated the selectable marker gene will survive, while the other cells die), among other methods.

The transformed cells can be cultured under conditions that promote expression of the polypeptide, and the polypeptide recovered by conventional protein purification procedures. Polypeptides contemplated for use herein include substantially homogeneous recombinant mammalian anti-mesothelin antibody or antigen binding polypeptides substantially free of contaminating endogenous materials.

Cells containing the nucleic acid encoding the antigen binding proteins of the present invention also include hybridomas. The production and culturing of hybridomas are discussed in the antibody section above.

Antigen Binding Protein and Antibody Production

The antigen binding proteins and antibodies of the invention can be produced by any method known in the art for the synthesis of antibodies, in particular, by chemical synthesis or preferably, by recombinant expression techniques.

Recombinant expression of an antigen binding protein or antibody of the invention, or fragment, derivative or analog thereof, (e.g., a heavy or light chain of an antibody of the invention or a single chain antibody of the invention), requires construction of an expression vector containing a polynucleotide that encodes the antigen binding protein or antibody or a fragment of the antibody or antigen binding protein. Once a polynucleotide encoding an antibody or antigen binding protein has been obtained, the vector for the production of the antibody or antigen binding protein may be produced by recombinant DNA technology. An expression vector is constructed containing antibody or antigen binding protein coding sequences and appropriate transcriptional and translational control signals. These methods include, for example, in vitro recombinant DNA techniques, synthetic techniques, and in vivo genetic recombination.

The expression vector is transferred to a host cell by conventional techniques and the transfected cells are then cultured by conventional techniques to produce an antibody or antigen binding protein of the invention. In one aspect of the invention, vectors encoding both the heavy and light chains may be co-expressed in the host cell for expression of the entire immunoglobulin molecule, as detailed below.

A variety of host-expression vector systems may be utilized to express the antibody or antigen binding protein of the invention as described above. Such host-expression systems represent vehicles by which the coding sequences of interest may be produced and subsequently purified, but also represent cells which may, when transformed or transfected with the appropriate nucleotide coding sequences, express an antibody or antigen binding protein of the invention in situ. Bacterial cells such as E. coli, and eukaryotic cells are commonly used for the expression of a recombinant antibody or antigen binding protein, especially for the expression of whole recombinant antibody molecule. For example, mammalian cells such as Chinese hamster ovary cells (CHO), in conjunction with a vector such as the major intermediate early gene promoter element from human cytomegalovirus is an effective expression system for antibodies (Foecking et al., Gene 45:101 (1986); Cockett et al., Bio/Technology 8:2 (1990)).

In addition, a host cell strain may be chosen which modulates the expression of the inserted sequences, or modifies and processes the gene product in the specific fashion desired. Such modifications (e.g., glycosylation) and processing (e.g., cleavage) of protein products may be important for the function of the protein. Different host cells have characteristic and specific mechanisms for the post-translational processing and modification of proteins and gene products. Appropriate cell lines or host systems can be chosen to ensure the correct modification and processing of the foreign protein expressed. To this end, eukaryotic host cells which possess the cellular machinery for proper processing of the primary transcript, glycosylation, and phosphorylation of the gene product may be used. Such mammalian host cells include, but are not limited to, CHO, COS, 293, 3T3, or myeloma cells.

For long-term, high-yield production of recombinant proteins, stable expression is preferred. For example, cell lines which stably express the antibody or antigen binding protein may be engineered. Rather than using expression vectors which contain viral origins of replication, host cells can be transformed with DNA controlled by appropriate expression control elements (e.g., promoter, enhancer, sequences, transcription terminators, polyadenylation sites, etc.), and a selectable marker. Following the introduction of the foreign DNA, engineered cells may be allowed to grow for 1-2 days in an enriched media, and then are switched to a selective media. The selectable marker in the recombinant plasmid confers resistance to the selection and allows cells to stably integrate the plasmid into their chromosomes and grow to form foci which in turn can be cloned and expanded into cell lines. This method may advantageously be used to engineer cell lines which express the antibody or antigen binding protein. Such engineered cell lines may be particularly useful in screening and evaluation of compounds that interact directly or indirectly with the antibody or antigen binding protein.

A number of selection systems may be used, including but not limited to the herpes simplex virus thymidine kinase (Wigler et al., Cell 11:223 (1977)), hypoxanthine-guanine phosphoribosyltransferase (Szybalska & Szybalski, Proc. Natl. Acad. Sci. USA 48:202 (1992)), and adenine phosphoribosyltransferase (Lowy et al., Cell 22:817 (1980)) genes can be employed in tk, hgprt or aprt-cells, respectively. Also, antimetabolite resistance can be used as the basis of selection for the following genes: dhfr, which confers resistance to methotrexate (Wigler et al., Proc. Natl. Acad. Sci. USA 77:357 (1980); O'Hare et al., Proc. Natl. Acad. Sci. USA 78:1527 (1981)); gpt, which confers resistance to mycophenolic acid (Mulligan & Berg, Proc. Natl. Acad. Sci. USA 78:2072 (1981)); neo, which confers resistance to the aminoglycoside G-418 (Wu and Wu, Biotherapy 3:87-95 (1991)); and hygro, which confers resistance to hygromycin (Santerre et al., Gene 30:147 (1984)). Methods commonly known in the art of recombinant DNA technology may be routinely applied to select the desired recombinant clone, and such methods are described, for example, in Ausubel et al. (eds.), Current Protocols in Molecular Biology, John Wiley & Sons, N Y (1993); Kriegler, Gene Transfer and Expression, A Laboratory Manual, Stockton Press, N Y (1990); and in Chapters 12 and 13, Dracopoli et al. (eds), Current Protocols in Human Genetics, John Wiley & Sons, N Y (1994); Colberre-Garapin et al., J. Mol. Biol. 150:1 (1981), which are incorporated by reference herein in their entireties.

The expression levels of an antibody or antigen binding protein can be increased by vector amplification (for a review, see Bebbington and Hentschel, “The use of vectors based on gene amplification for the expression of cloned genes in mammalian cells” (DNA Cloning, Vol. 3. Academic Press, New York, 1987)). When a marker in the vector system expressing antibody or antigen binding protein is amplifiable, increase in the level of inhibitor present in culture of host cell will increase the number of copies of the marker gene. Since the amplified region is associated with the antibody gene, production of the antibody or antigen binding protein will also increase (Crouse et al., Mol. Cell. Biol. 3:257 (1983)).

The host cell may be co-transfected with two expression vectors of the invention, the first vector encoding a heavy chain derived polypeptide and the second vector encoding a light chain derived polypeptide. The two vectors may contain identical selectable markers which enable equal expression of heavy and light chain polypeptides. Alternatively, a single vector may be used which encodes, and is capable of expressing, both heavy and light chain polypeptides. In such situations, the light chain should be placed before the heavy chain to avoid an excess of toxic free heavy chain (Proudfoot, Nature 322:52 (1986); Kohler, Proc. Natl. Acad. Sci. USA 77:2197 (1980)). The coding sequences for the heavy and light chains may comprise cDNA or genomic DNA.

Once an antibody or antigen binding protein of the invention has been produced by an animal, chemically synthesized, or recombinantly expressed, it may be purified by any method known in the art for purification of an immunoglobulin molecule, for example, by chromatography (e.g., ion exchange, affinity, particularly by affinity for the specific antigen after Protein A, and size-exclusion chromatography), centrifugation, differential solubility, or by any other standard technique for the purification of proteins. In addition, the antibodies of the present invention or fragments thereof can be fused to heterologous polypeptide sequences described herein or otherwise known in the art, to facilitate purification.

The present invention encompasses antibodies recombinantly fused or chemically conjugated (including both covalently and non-covalently conjugations) to a polypeptide. Fused or conjugated antibodies of the present invention may be used for ease in purification. See e.g., Harbor et al., supra, and PCT publication WO 93/21232; EP 439,095; Naramura et al., Immunol. Lett. 39:91-99 (1994); U.S. Pat. No. 5,474,981; Gillies et al., Proc. Natl. Acad. Sci. 89:1428-1432 (1992); Fell et al., J. Immunol. 146:2446-2452 (1991).

Moreover, the antibodies or fragments thereof of the present invention can be fused to marker sequences, such as a peptide to facilitate purification. In preferred embodiments, the marker amino acid sequence is a hexa-histidine peptide, such as the tag provided in a pQE vector (QIAGEN, Inc., 9259 Eton Avenue, Chatsworth, Calif., 91311), among others, many of which are commercially available. As described in Gentz et al., Proc. Natl. Acad. Sci. USA 86:821-824 (1989), for instance, hexa-histidine provides for convenient purification of the fusion protein. Other peptide tags useful for purification include, but are not limited to, the “HA” tag, which corresponds to an epitope derived from the influenza hemagglutinin protein (Wilson et al., Cell 37:767 (1984)) and the “flag” tag.

Binding to Mesothelin

In one embodiment, the present invention provides antigen binding proteins that compete for binding with a reference antibody or antigen binding protein, wherein the reference antibody or antigen binding protein comprises a combination of light chain and heavy chain variable domain sequences selected from the sequences provided herein. In another embodiment, the present invention provides human antibodies or antigen binding proteins that cross-compete for binding with a reference antibody, wherein the reference antibody is Ab237, Ab1.1.2, Ab1.33.1, Ab1.68.1, Ab1.78.1, Ab1.119.1, or Ab2.69.2. The ability to cross-compete with an antibody can be determined using any suitable assay, with nonlimiting examples further described below.

Epitope

As described herein, an epitope is the portion of a molecule that is bound by an antigen binding protein (e.g., an antibody). An epitope can comprise non-contiguous portions of the molecule (e.g., in a polypeptide, amino acid residues that are not contiguous in the polypeptide's primary sequence but that, in the context of the polypeptide's tertiary and quaternary structure, are near enough to each other to be bound by an antibody or antigen binding protein). Further, an epitope can comprise or consist of simply a linear, contiguous polypeptide sequence. In determining binding of an antigen binding protein to a target molecule, one skilled in the art can, for example, determine if the antigen binding protein competes for the same epitope as compared to another antigen binding protein or, e.g., the known ligand or receptor of the target molecule.

The term “compete” or “cross-compete” when used in the context of antigen binding proteins (e.g., neutralizing antigen binding proteins or neutralizing antigen binding proteins or non-neutralizing antigen binding proteins) that compete for the same epitope means competition between antigen binding proteins as determined by an assay in which the antigen binding protein (e.g., antibody or immunologically functional fragment thereof) being tested prevents or inhibits (e.g., reduces) specific binding of a reference antigen binding protein (e.g., a ligand, or a reference antibody) to a common antigen (e.g., PCSK9 or a fragment thereof).

Numerous competition assays are well known in the art, with nonlimiting examples being competition ELISA, use of the BiaCore® platform, the Kinexa® platform, or the like. Further examples include: solid phase direct or indirect radioimmunoassay (MA), solid phase direct or indirect enzyme immunoassay (EIA), sandwich competition assay (see, e.g., Stahli et al., 1983, Methods in Enzymology 9:242-253); solid phase direct biotin-avidin EIA (see, e.g., Kirkland et al., 1986, J. Immunol. 137:3614-3619) solid phase direct labeled assay, solid phase direct labeled sandwich assay (see, e.g., Harlow and Lane, 1988, Antibodies, A Laboratory Manual, Cold Spring Harbor Press); solid phase direct label RIA using 1-125 label (see, e.g., Morel et al., 1988, Molec. Immunol. 25:7-15); solid phase direct biotin-avidin EIA (see, e.g., Cheung, et al., 1990, Virology 176:546-552); and direct labeled RIA (Moldenhauer et al., 1990, Scand. J. Immunol. 32:77-82). Typically, such an assay involves the use of purified antigen bound to a solid surface or cells bearing either of these, an unlabelled test antigen binding protein and a labeled reference antigen binding protein. Competitive inhibition is measured by determining the amount of label bound to the solid surface or cells in the presence of the test antigen binding protein. Usually the test antigen binding protein is present in excess. Antigen binding proteins identified by competition assay (competing antigen binding proteins) include antigen binding proteins binding to the same epitope as the reference antigen binding proteins and antigen binding proteins binding to an adjacent epitope sufficiently proximal to the epitope bound by the reference antigen binding protein for steric hindrance to occur. Usually, when a competing antigen binding protein is present in excess, it will inhibit (e.g., reduce) specific binding of a reference antigen binding protein to a target antigen by at least 40-45%, 45-50%, 50-55%, 55-60%, 60-65%, 65-70%, 70-75% or 75% or more. In some embodiments, binding is inhibited by at least 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%. In some embodiments, binding is inhibited by at least 80-85%, 85-90%, 90-95%, 95-97%, or 97% or more.

Accordingly, the invention provides anti-human mesothelin antibodies that compete for binding with the antibodies of the invention. In one embodiment, the invention provides for antibodies that compete for binding with Ab237. In one embodiment, the invention provides for antibodies that compete for binding with Ab1.1.2. In one embodiment, the invention provides for antibodies that compete for binding with Ab1.33.1. In one embodiment, the invention provides for antibodies that compete for binding with Ab1.33.1y. In one embodiment, the invention provides for antibodies that compete for binding with Ab1.68.1. In one embodiment, the invention provides for antibodies that compete for binding with Ab1.78.1. In one embodiment, the invention provides for antibodies that compete for binding with Ab1.119.1. In one embodiment, the invention provides for antibodies that compete for binding with Ab2.69.2. In one embodiment, the invention provides for antibodies that compete for binding with Ab2.69.2cv. In one embodiment, the invention provides for antibodies that compete for binding with Ab2.69.2s. In one embodiment, the invention provides for antibodies that compete for binding with Ab1.58. In one embodiment, the invention provides for antibodies that compete for binding with Ab1.51.

Activity of Antigen Binding Proteins

In certain embodiments, the present invention provides antigen binding proteins, in particular human, humanized, or chimeric antibodies, that specifically bind to human mesothelin. In another embodiment, the present invention provides antigen binding proteins that specifically bind to cynomologous mesothelin. In another embodiment, the present invention provides antigen binding proteins that specifically bind to murine mesothelin. In another embodiment, the present invention provides antigen binding proteins that specifically bind to rat mesothelin. In another embodiment, the present invention provides antigen binding proteins that specifically bind to human, cynomologous, murine and rat mesothelin. In another embodiment, the present invention provides antigen binding proteins that specifically bind to human, cynomologous and murine mesothelin. In another embodiment, the present invention provides antigen binding proteins that specifically bind to human and cynomologous mesothelin. In another embodiment, the present invention provides antigen binding proteins that specifically bind to human and murine mesothelin. In another embodiment, the present invention provides antigen binding proteins that specifically bind to human and rat mesothelin. Such antibodies include antagonizing or neutralizing antibodies.

In certain embodiments, the antigen binding proteins of the invention, such as the human antibodies of the present invention have an IC50 value of 90 nM or less, in another embodiment, an IC50 value of 80 nM or less, in another embodiment, 70 nM or less, in another embodiment, 60 nM or less, in another embodiment, 50 nM or less, in another embodiment, 40 nM or less, in another embodiment, 30 nM or less, in another embodiment 25 nM or less.

In certain embodiments, the antigen binding proteins of the invention do not interernalize into the cell that expresses MSLN upon binding to MSLN. This is an advantageous and unexpected property, as in certain embodiments it is desirable to keep the antigen binding protein exposed at the cell surface. For example, for effector cell mediated killing of the cell expressing MSLN (e.g., ADCC), it is desirable to maintain the antigen binding protein at the cell surface so that effector cells can bind to, e.g., the Fc region of an antigen binding protein. In another nonlimiting example such as a bispecific single chain antibody that binds to MSLN and CD3, it is desirable to maintain this antibody at the cell surface so that the CD3 expressing effector cells can efficiently be brought into proximity of the MSLN expressing target cell. Determining whether an antigen binding protein of the invention internalizes or not can be readily determined using assays well known in the art.

In certain embodiments, the antigen binding proteins of the invention do not inhibit or interfere with the MSLN/CA125 interaction. Although the significance of the MSLN and CA125 interaction has not been fully elucidated, as described herein, it is known that this interaction plays a role in cell adhesion and may also play a role in tumor metastasis. Analysis of the MSLN/CA125 interaction can be readily determined using assays well known in the art. Nonlimiting examples include using competition assays described herein. In some embodiments the antigen binding proteins of the invention inhibit or interfere with the MSLN/CA125 interaction by less than about 1%, 2%, 3%, 4%, 5%, 10%, 15%, or 20%. In some embodiments, the antigen binding proteins of the invention inhibit or interfere with the MSLN/CA125 interaction by less than about 0.1% to about 1%, less than about 1% to about 5%, less than about 1% to about 10%, less than about 1% to about 15% or less than about 1% to about 20%.

In certain embodiments, the antibody or antigen binding proteins of the invention specifically bind to MSLN have a dissociation constant or K_(d) (k_(off)/k_(on)) of less than 10⁻²M, less than 5e10⁻²M, less than 10⁻³M, less than 5e10⁻³M, less than 10⁻⁴M, less than 5e10⁻⁴M, less than 10⁻⁵M, less than 5e10⁻⁵M, less than 10⁻⁶M, less than 5e10⁻⁶M, less than 10⁻⁷M, less than 5e10⁻⁷M, less than 10⁻⁸M, less than 5e10⁻⁸M, less than 10⁻⁹M, less than 5e10⁻⁹M, less than 10⁻¹⁰M, less than 5e10⁻¹⁰M, less than 10⁻¹¹M, less than 5e10⁻¹¹M, less than 10⁻⁻¹²M, less than 5e10⁻¹²M, less than 10⁻⁻¹³M, less than 5e10⁻¹³M, less than 10⁻⁻¹⁴M, less than 5e10⁻¹⁴M, less than 10⁻⁻¹⁵M, or less than 5e10⁻¹⁵M. In a further embodiment, an ADC that specifically binds to least on Eph receptor has a dissociation constant or K.sub.d (k.sub.off/k.sub.on) of less than about 10⁻²M, less than about 5e10⁻²M, less than about 10⁻³M, less than about 5e10⁻³M, less than about 10⁻⁴M, less than about 5e10⁻⁴M, less than about 10⁻⁵M, less than about 5e10⁻⁵M, less than about 10⁻⁶M, less than about 5e10⁻⁶M, less than about 10⁻⁷M, less than about 5e10⁻⁷M, less than about 10⁻⁸M, less than about 5e10⁻⁸M, less than about 10⁻⁹M, less than about 5e10⁻⁹M, less than about 10⁻¹⁰M, less than about 5e10⁻¹⁰M, less than about 10⁻¹¹M, less than about 5e10⁻¹¹M, less than about 10⁻⁻¹²M, less than about 5e10⁻¹²M, less than about 10⁻⁻¹³M, less than about 5e10⁻¹³M, less than about 10⁻⁻¹⁴M, less than about 5e10⁻¹⁴M, less than about 10⁻⁻¹⁵M, or less than about 5e10¹⁵M.

In another embodiment, an antibody or antigen binding protein that specifically binds to MSLN has a K_(d) of greater than 10⁻⁹ M, greater than 5e10⁻⁹ M, greater than 10⁻¹⁰ M, greater than 5e10⁻¹⁰ M, greater than 10⁻¹¹ M, greater than 5e10⁻¹¹ M, greater than 10⁻¹² M, greater than 5e10⁻¹² M, greater than 10⁻¹³ M, greater than 5e10⁻¹³ M, greater than 10⁻¹⁴ M, greater than 5e10⁻¹⁴ M or greater than 10⁻¹⁴ M. In another embodiment, an antibody or antigen binding protein that specifically binds to MSLN has a K_(d) of greater than about 10⁻⁹ M, greater than about 5e10⁻⁹ M, greater than about 10⁻¹⁰ M, greater than about 5e10⁻¹⁰ M, greater than about 10⁻¹¹ M, greater than about 5e10⁻¹¹ M, greater than about 10⁻¹² M, greater than about 5e10⁻¹² M, greater than about 10⁻¹³ M, greater than about 5e10⁻¹³ M, greater than about 10⁻¹⁴ M, greater than about 5e10⁻¹⁴ M or greater than about 10⁻¹⁴ M.

In a further embodiment, an antibody or antigen binding protein that specifically binds to MSLN has a K_(d) of between about 10⁻⁹ M and about 10⁻¹⁴ M, between about 10⁻⁹ M and about 10⁻¹³ M, between about 10⁻⁹ M and about 10⁻¹² M, between about 10⁻⁹ M and about 10⁻¹¹ M, or between about 10⁻⁹ M and about 10⁻¹⁰ M. In a further embodiment, an antibody or antigen binding protein that specifically binds to MSLN has a K_(d) of between about 10⁻⁹ M and about 10⁻¹⁴ M, between about 10⁻¹⁰ M and about 10⁻¹⁴ M, between about 10⁻¹¹ M and about 10⁻¹⁴ M, between about 10⁻¹² M and about 10⁻¹⁴ M, or between about 10⁻¹³ M and about 10⁻¹⁴ M. In a further embodiment, an antibody or antigen binding protein that specifically binds to MSLN has a K_(d) of between 10⁻⁹ M and 10⁻¹⁴ M, between 10⁻⁹ M and 10⁻¹³ M, between 10⁻⁹ M and 10⁻¹² M, between 10⁻⁹ M and 10⁻¹¹ M, or between 10⁻⁹ M and 10⁻¹⁰ M. In a further embodiment, an antibody or antigen binding protein that specifically binds to MSLN has a K_(d) of between 10⁻⁹ M and 10⁻¹⁴ M, between 10⁻¹⁰ M and 10⁻¹⁴ M, between 10⁻¹¹ M and 10⁻¹⁴ M, between 10⁻¹² M and 10⁻¹⁴ M, or between 10⁻¹³ M and 10⁻¹⁴ M.

K_(d) for the antigen binding proteins of the invention can be readily determined by assays well known in the art. Nonlimiting examples include the BIAcore® platform or the Kinexa® platform as described herein.

In certain embodiments, the antigen binding proteins of the invention preferentially bind membrane bound MSLN over soluble MSLN. Membrane bound MSLN refers to the presence of MSLN in or on the cell membrane surface of a cell that expresses MSLN. Soluble MSLN refers to MSLN that is no longer on in or on the cell membrane surface of a cell that expresses or expressed MSLN. In certain instances, the soluble MSLN is present in the blood and/or lymphatic circulation in a subject. In one embodiment, the antigen binding proteins bind membrane-bound mesothelin at least 5 fold, 10 fold, 15 fold, 20 fold, 25 fold, 30 fold, 40 fold, 50 fold, 100 fold, 500 fold, or 1000 fold greater than soluble mesothelin. In one embodiment, the antigen binding proteins of the present invention preferentially bind membrane-bound mesothelin 30 fold greater than soluble mesothelin. Determining the preferential binding of an antigen binding protein to membrane bound MSLN over soluble MSLN can be readily determined using assays well known in the art. Nonlimiting examples are competition assays as described herein.

In certain embodiments, the antigen binding molecules of the invention reduces the growth of tumor cells in vivo when administered to a subject who has tumor cells that express MSLN. Measurement of the reduction of the growth of tumor cells can be determined by multiple different methodologies well known in the art. Nonlimiting examples include direct measurement of tumor dimension, measurement of excised tumor mass and comparison to control subjects, measurement via imaging techniques (e.g. CT or MRI) that may or may not use isotopes or luminescent molecules (e.g. luciferase) for enhanced analysis, and the like. In specific embodiments, administration of the antigen binding agents of the invention results in a reduction of in vivo growth of tumor cells as compared to a control antigen binding agent by at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%, with an about 100% reduction in tumor growth indicating a complete response and disappearance of the tumor. In further embodiments, administration of the antigen binding agents of the invention results in a reduction of in vivo growth of tumor cells as compared to a control antigen binding agent by about 50-100%, about 75-100% or about 90-100%. In further embodiments, administration of the antigen binding agents of the invention results in a reduction of in vivo growth of tumor cells as compared to a control antigen binding agent by about 50-60%, about 60-70%, about 70-80%, about 80-90%, or about 90-100%. Dosing can readily be determined by one skilled in the art and is discussed further herein.

Antibody or Antigen Binding Protein Effector Function

The present invention provides anti-mesothelin binding molecules with increased effector function. Nonlimiting examples of methods for increasing effector function can be found in U.S. Pat. Nos. 5,624,821, 6,602,684, 7,029,872, U.S. Patent Application Publication Nos. 2006/0067930A1, 2005/0272128A1, 2005/0079605A1, 2005/0123546A1, 2004/0072290A1, 2006/0257399A1, 2004/0261148A1, 2007/0092521, 2006/0040325A1, and 2006/0039904A1, and International Patent Application Publication Nos. WO 04/029207, WO03011878, WO05044859, WO 06071856, and WO 06071280.

Methods of engineering Fc regions of antibodies so as to alter effector functions are known in the art (e.g., U.S. Patent Publication No. 20040185045 and PCT Publication No. WO 2004/016750, both to Koenig et al., which describe altering the Fc region to enhance the binding affinity for Fc gamma RIIB as compared with the binding affinity for FC gamma RIIA; see, also, PCT Publication Nos. WO 99/58572 to Armour et al., WO 99/51642 to Idusogie et al., and U.S. Pat. No. 6,395,272 to Deo et al.). Methods of modifying the Fc region to decrease binding affinity to Fc gamma RIIB are also known in the art (e.g., U.S. Patent Publication No. 20010036459 and PCT Publication No. WO 01/79299, both to Ravetch et al.). Modified antibodies having variant Fc regions with enhanced binding affinity for Fc gamma RIIIA and/or Fc gamma RIIA as compared with a wildtype Fc region have also been described (e.g., PCT Publication Nos. WO 2004/063351, to Stavenhagen et al., the disclosure of which is incorporated herein in its entirety). Throughout the specification, and in particular the examples, the terms “2×” and “3×” in reference to the anti-MSLN antibodies are used. These terms refer to substitutions in the Fc region that result in enhanced ADCC through increased binding affinity to the Fc receptor as described above. In one embodiment, the “2×” molecule has the following substitutions: S239D/I332E and the “3×” molecule has the following mutations: S239D/I332E/A330L.

Antibody or antigen binding protein effector function may also be modified through the generation of antibodies with altered glycosylation patterns. In the present invention, such antibodies may be referred to as “low fucose” antibodies. For example, an antibody or antigen binding protein can be made that has an altered type of glycosylation, such as an afucosylated/hypofucosylated antibody or antigen binding protein having reduced amounts of fucosyl residues or an antibody or antigen binding protein having increased bisecting GlcNac structures. Such altered glycosylation patterns have been demonstrated to increase the ADCC ability of antibodies. Such carbohydrate modifications can be accomplished by, for example, expressing the antibody or antigen binding protein in a host cell with altered glycosylation machinery. Cells with altered glycosylation machinery have been described in the art and can be used as host cells in which to express recombinant antibodies of the invention to thereby produce an antibody or antigen binding protein with altered glycosylation. For example, EP 1,176,195 by Hanai et al. describes a cell line with a functionally disrupted FUT8 gene, which encodes a fucosyl transferase, such that antibodies expressed in such a cell line exhibit hypofucosylation. PCT Publication WO 03/035835 by Presta describes a variant CHO cell line, Lec13 cells, with reduced ability to attach fucose to Asn(297)-linked carbohydrates, also resulting in hypofucosylation of antibodies expressed in that host cell (see also Shields, R. L. et al. (2002) J. Biol. Chem. 277:26733-26740). PCT Publication WO 99/54342 by Umana et al. describes cell lines engineered to express glycoprotein-modifying glycosyl transferases (e.g., beta(1,4)—N-acetylglucosaminyltransferase III (GnTIII)) such that antibodies expressed in the engineered cell lines exhibit increased bisecting GlcNac structures which results in increased ADCC activity of the antibodies (see also Umana et al. (1999) Nat. Biotech. 17:176-180). PCT Publication WO 2009009086 by Collingwood et al. describes the use of zinc finger constructs to inactivate the FUT8 gene in cells.

Methods for generating antibodies with altered glycoforms are known in the art, and include but are not limited to those described in Umana et al, 1999, Nat. Biotechnol 17:176-180; Davies et al., 20017 Biotechnol Bioeng 74:288-294; Shields et al, 2002, J Biol Chem 277:26733-26740; Shinkawa et al., 2003; J Biol Chem 278:3466-3473) U.S. Pat. No. 6,602,684; U.S. Ser. No. 10/277,370; U.S. Ser. No. 10/113,929; PCT WO 00/61739A1; PCT WO 01/292246A1; PCT WO 02/311140A1; PCT WO 02/30954A1; Potillegent™ technology (Biowa, Inc. Princeton, N.J.); and GlycoMAb™ glycosylation engineering technology (GLYCART biotechnology AG, Zurich, Switzerland). See, e.g., WO 00061739; EA01229125; US 20030115614; Okazaki et al., 2004, JMB, 336: 1239-49. It is contemplated that antibodies with altered fucosylation pattern may also be prepared by post-translational removal of fucose (e.g. with a fucosidase enzyme).

Half-Life

The present invention provides for antibodies or antigen binding protein or fragments thereof that specifically bind to mesothelin which have an extended half-life in vivo. In particular, the present invention provides antibodies or antigen binding protein or fragments thereof which have a half-life in a mammal (for example, but not limited to, a human), of greater than 3 days, greater than 7 days, greater than 10 days, greater than 15 days, greater than 25 days, greater than 30 days, greater than 35 days, greater than 40 days, greater than 45 days, greater than 2 months, greater than 3 months, greater than 4 months, or greater than 5 months.

To prolong the serum circulation of antibodies (for example, but not limited to, monoclonal antibodies and single chain antibodies) or antigen binding protein or fragments thereof (for example, but not limited to, Fab fragments) in vivo, for example, inert polymer molecules such as high molecular weight polyethyleneglycol (PEG) can be attached to the antibodies or antigen binding proteins (including fragments thereof) with or without a multifunctional linker either through site-specific conjugation of the PEG to the N- or C-terminus of the antibodies or via epsilon-amino groups present on lysine residues. Linear or branched polymer derivatization that results in minimal loss of biological activity will be used. The degree of conjugation can be closely monitored by SDS-PAGE and mass spectrometry to ensure proper conjugation of PEG molecules to the antibodies. Unreacted PEG can be separated from antibody- or antigen binding proteins-PEG conjugates by size-exclusion or by ion-exchange chromatography. PEG-derivatized antibodies or antigen binding proteins (including fragments thereof) can be tested for binding activity as well as for in vivo efficacy using methods known to those of skill in the art, for example, by immunoassays described herein.

Antibodies having an increased half-life in vivo can also be generated by introducing one or more amino acid modifications (i.e., substitutions, insertions or deletions) into an IgG constant domain, or FcRn binding fragment thereof (e.g., Fc or hinge Fc domain fragment). See, e.g., International Publication No. WO 98/23289; International Publication No. WO 97/34631; and U.S. Pat. No. 6,277,375, each of which is incorporated herein by reference in its entirety.

Conjugates

According to certain aspects of the invention, therapeutic agents or toxins can be conjugated to chimerized, human, or humanized anti-mesothelin antibodies for use in the compositions and methods of the invention. In certain embodiments, these conjugates can be generated as fusion proteins. Examples of therapeutic agents and toxins include, but are not limited to, members of the enediyne family of molecules, such as calicheamicin and esperamicin. Chemical toxins can also be taken from the group consisting of duocarmycin (see, e.g., U.S. Pat. Nos. 5,703,080 and 4,923,990), methotrexate, doxorubicin, melphalan, chlorambucil, ARA-C, vindesine, mitomycin C, cis-platinum, etoposide, bleomycin and 5-fluorouracil. Examples of chemotherapeutic agents also include Adriamycin, Doxorubicin, 5-Fluorouracil, Cytosine arabinoside (Ara-C), Cyclophosphamide, Thiotepa, Taxotere (docetaxel), Busulfan, Cytoxin, Taxol, Methotrexate, Cisplatin, Melphalan, Vinblastine, Bleomycin, Etoposide, Ifosfamide, Mitomycin C, Mitoxantrone, Vincreistine, Vinorelbine, Carboplatin, Teniposide, Daunomycin, Caminomycin, Aminopterin, Dactinomycin, Mitomycins, Esperamicins (see, U.S. Pat. No. 4,675,187), Melphalan, and other related nitrogen mustards.

Other toxins that can be used in the immunoconjugates of the invention include poisonous lectins, plant toxins such as ricin, abrin, modeccin, botulina, and diphtheria toxins. Combinations of the various toxins could also be coupled to one antibody or antigen binding protein thereby accommodating variable cytotoxicity. Nonlimiting examples of toxins which are suitably employed in the combination therapies of the invention are ricin, abrin, ribonuclease, DNase I, Staphylococcal enterotoxin-A, pokeweed anti-viral protein, gelonin, diphtherin toxin, Pseudomonas exotoxin, and Pseudomonas endotoxin. See, for example, Pastan et al., Cell, 47:641 (1986), and Goldenberg et al., Cancer Journal for Clinicians, 44:43 (1994). Enzymatically active toxins and fragments thereof which can be used include diphtheria A chain, non-binding active fragments of diphtheria toxin, exotoxin A chain (from Pseudomonas aeruginosa), ricin A chain, abrin A chain, modeccin A chain, alpha-sarcin, Aleurites fordii proteins, dianthin proteins, Phytolaca americana proteins (PAPI, PAPII, and PAP-S), Momordica charantia inhibitor, curcin, crotin, Sapaonaria officinalis inhibitor, gelonin, mitogellin, restrictocin, phenomycin, enomycin and the tricothecenes. See, for example, WO 93/21232 published Oct. 28, 1993. Suitable toxins and chemotherapeutic agents are described in Remington's Pharmaceutical Sciences, 19th Ed. (Mack Publishing Co. 1995), and in Goodman And Gilman's The Pharmacological Basis of Therapeutics, 7th Ed. (MacMillan Publishing Co. 1985). Other suitable toxins and/or chemotherapeutic agents are known to those of skill in the art.

Enzymes that are useful in the method of this invention include, but are not limited to, alkaline phosphatase useful for converting phosphate-containing prodrugs into free drugs; arylsulfatase useful for converting sulfate-containing prodrugs into free drugs; cytosine deaminase useful for converting non-toxic 5-fluorocytosine into the anti-cancer drug, 5-fluorouracil; proteases, such as serratia protease, thermolysin, subtilisin, carboxypeptidases and cathepsins (such as cathepsins B and L), that are useful for converting peptide-containing prodrugs into free drugs; D-alanylcarboxypeptidases, useful for converting prodrugs that contain D-amino acid substituents; carbohydrate-cleaving enzymes such as beta-galactosidase and neuraminidase useful for converting glycosylated prodrugs into free drugs; beta-lactamase useful for converting drugs derivatized with alpha-lactams into free drugs; and penicillin amidases, such as penicillin V amidase or penicillin G amidase, useful for converting drugs derivatized at their amine nitrogens with phenoxyacetyl or phenylacetyl groups, respectively, into free drugs. Alternatively, antibodies with enzymatic activity, also known in the art as “abzymes,” can be used to convert the prodrugs of the invention into free active drugs (see, e.g., Massey, Nature 328:457-458 (1987)). Antibody-abzyme conjugates can be prepared as described herein for delivery of the abzyme as desired to portions of a human affected by a B cell malignancy.

The enzymes can be covalently bound to the antibodies of the present invention by techniques well-known in the art such as the use of the heterobifunctional crosslinking reagents discussed above. Alternatively, fusion proteins comprising at least the antigen-binding region of an antibody of the invention linked to at least a functionally active portion of an enzyme of the invention can be constructed using recombinant DNA techniques well-known in the art (see, e.g., Neuberger et al., Nature, 312:604-608 (1984)).

Covalent modifications of the anti-mesothelin antibody or antigen binding proteins of the invention are included within the scope of this invention. They may be made by chemical synthesis or by enzymatic or chemical cleavage of the antibody or antigen binding proteins, if applicable. Other types of covalent modifications of the anti-mesothelin antibody or antigen binding proteins are introduced into the molecule by reacting targeted amino acid residues of the antibody or antigen binding proteins with an organic derivatizing agent that is capable of reacting with selected side chains or the N- or C-terminal residues.

Cysteinyl residues most commonly are reacted with alpha-haloacetates (and corresponding amines), such as chloroacetic acid or chloroacetamide, to give carboxymethyl or carboxyamidomethyl derivatives. Similarly, iodo-reagents may also be used. Cysteinyl residues also are derivatized by reaction with bromotrifluoroacetone, alpha-bromo-beta-(5-imidozoyl)propionic acid, chloroacetyl phosphate, N-alkylmaleimides, 3-nitro-2-pyridyl disulfide, methyl 2-pyridyl disulfide, p-chloromercuribenzoate, 2-chloromercuri-4-nitrophenol, or chloro-7-nitrobenzo-2-oxa-1,3-diazole.

Histidyl residues are derivatized by reaction with diethylpyrocarbonate at pH 5.5-7.0 because this agent is relatively specific for the histidyl side chain. Para-bromophenacyl bromide also is useful; the reaction is preferably performed in 0.1 M sodium cacodylate at pH 6.0.

Lysyl and amino-terminal residues are reacted with succinic or other carboxylic acid anhydrides. Derivatization with these agents has the effect of reversing the charge of the lysinyl residues. Other suitable reagents for derivatizing .alpha.-amino-containing residues and/or e-amino-containing residues include imidoesters such as methyl picolinimidate, pyridoxal phosphate, pyridoxal, chloroborohydride, trinitrobenzenesulfonic acid, 0-methylisourea, 2,4-pentanedione, and transaminase-catalyzed reaction with glyoxylate.

Arginyl residues are modified by reaction with one or several conventional reagents, among them phenylglyoxal, 2,3-butanedione, 1,2-cyclohexanedione, and ninhydrin. Derivatization of arginyl residues generally requires that the reaction be performed in alkaline conditions because of the high pKa of the guanidine functional group. Furthermore, these reagents may react with the epsilon-amino groups of lysine as well as the arginine epsilon-amino group.

The specific modification of tyrosyl residues may be made, with particular interest in introducing spectral labels into tyrosyl residues by reaction with aromatic diazonium compounds or tetranitromethane. Most commonly, N-acetylimidizole and tetranitromethane are used to form O-acetyl tyrosyl species and 3-nitro derivatives, respectively. Tyrosyl residues are iodinated using I¹²⁵ or I¹³¹ to prepare labeled proteins for use in radioimmunoassay.

Carboxyl side groups (aspartyl or glutamyl) are selectively modified by reaction with carbodiimides (R—N═C═N—R′), where R and R′ are different alkyl groups, such as 1-cyclohexyl-3-(2-morpholinyl-4-ethyl)carbodiimide or 1-ethyl-3-(4-azonia-4,4-dimethylpentyl)carbodiimide. Furthermore, aspartyl and glutamyl residues are converted to asparaginyl and glutaminyl residues by reaction with ammonium ions.

Glutaminyl and asparaginyl residues are frequently deamidated to the corresponding glutamyl and aspartyl residues, respectively. These residues are deamidated under neutral or basic conditions. The deamidated form of these residues falls within the scope of this invention.

Other modifications include hydroxylation of proline and lysine, phosphorylation of hydroxyl groups of seryl or threonyl residues, methylation of the .alpha.-amino groups of lysine, arginine, and histidine side chains (T. E. Creighton, Proteins: Structure and Molecular Properties, W.H. Freeman & Co., San Francisco, pp. 79-86 (1983)), acetylation of the N-terminal amine, and amidation of any C-terminal carboxyl group.

Another type of covalent modification involves chemically or enzymatically coupling glycosides to the antibody or antigen binding proteins. These procedures are advantageous in that they do not require production of the antibody or antigen binding proteins in a host cell that has glycosylation capabilities for N- or O-linked glycosylation. Depending on the coupling mode used, the sugar(s) may be attached to (a) arginine and histidine, (b) free carboxyl groups, (c) free sulfhydryl groups such as those of cysteine, (d) free hydroxyl groups such as those of serine, threonine, or hydroxyproline, (e) aromatic residues such as those of phenylalanine, tyrosine, or tryptophan, or (f) the amide group of glutamine. These methods are described in WO 87/05330 published 11 Sep. 1987, and in Aplin and Wriston, CRC Crit. Rev. Biochem., pp. 259-306 (1981).

Methods of Treatment

In another aspect, a method of treating a subject, comprising administering a therapeutic dosage of the antigen binding proteins of the present invention is provided. In one embodiment, the antigen binding proteins are human antibodies. As used herein the term “subject” refers to a mammal, including humans, and is used interchangeably with the term “patient”. The human antibodies, can be used to treat, control or prevent a disorder or condition characterized by cells expressing or overexpressing mesothelin in a subject. These disorders include cancer and other hyperproliferative disorders characterized by expression or overexpression of mesothelin.

Cancers and related disorders that can be treated, prevented, or managed by methods and compositions of the present invention include but are not limited to cancers of an epithelial cell origin. Examples of such cancers include the following: leukemias, such as but not limited to, acute leukemia, acute lymphocytic leukemia, acute myelocytic leukemias, such as, myeloblastic, promyelocytic, myelomonocytic, monocytic, and erythroleukemia leukemias and myelodysplastic syndrome; chronic leukemias, such as but not limited to, chronic myelocytic (granulocytic) leukemia, chronic lymphocytic leukemia, hairy cell leukemia; polycythemia vera; lymphomas such as but not limited to Hodgkin's disease, non-Hodgkin's disease; multiple myelomas such as but not limited to smoldering multiple myeloma, nonsecretory myeloma, osteosclerotic myeloma, plasma cell leukemia, solitary plasmacytoma and extramedullary plasmacytoma; Waldenstrom's macroglobulinemia; monoclonal gammopathy of undetermined significance; benign monoclonal gammopathy; heavy chain disease; bone and connective tissue sarcomas such as but not limited to bone sarcoma, osteosarcoma, chondrosarcoma, Ewing's sarcoma, malignant giant cell tumor, fibrosarcoma of bone, chordoma, periosteal sarcoma, soft-tissue sarcomas, angiosarcoma (hemangiosarcoma), fibrosarcoma, Kaposi's sarcoma, leiomyosarcoma, liposarcoma, lymphangiosarcoma, neurilemmoma, rhabdomyosarcoma, synovial sarcoma; brain tumors such as but not limited to, glioma, astrocytoma, brain stem glioma, ependymoma, oligodendroglioma, nonglial tumor, acoustic neurinoma, craniopharyngioma, medulloblastoma, meningioma, pineocytoma, pineoblastoma, primary brain lymphoma; breast cancer including but not limited to ductal carcinoma, adenocarcinoma, lobular (small cell) carcinoma, intraductal carcinoma, medullary breast cancer, mucinous breast cancer, tubular breast cancer, papillary breast cancer, Paget's disease, and inflammatory breast cancer; adrenal cancer such as but not limited to pheochromocytom and adrenocortical carcinoma; thyroid cancer such as but not limited to papillary or follicular thyroid cancer, medullary thyroid cancer and anaplastic thyroid cancer; pancreatic cancer such as but not limited to, insulinoma, gastrinoma, glucagonoma, vipoma, somatostatin-secreting tumor, and carcinoid or islet cell tumor; pituitary cancers such as but limited to Cushing's disease, prolactin-secreting tumor, acromegaly, and diabetes insipius; eye cancers such as but not limited to ocular melanoma such as iris melanoma, choroidal melanoma, and cilliary body melanoma, and retinoblastoma; vaginal cancers such as squamous cell carcinoma, adenocarcinoma, and melanoma; vulvar cancer such as squamous cell carcinoma, melanoma, adenocarcinoma, basal cell carcinoma, sarcoma, and Paget's disease; cervical cancers such as but not limited to, squamous cell carcinoma, and adenocarcinoma; uterine cancers such as but not limited to endometrial carcinoma and uterine sarcoma; ovarian cancers such as but not limited to, ovarian epithelial carcinoma, borderline tumor, germ cell tumor, and stromal tumor; esophageal cancers such as but not limited to, squamous cancer, adenocarcinoma, adenoid cystic carcinoma, mucoepidermoid carcinoma, adenosquamous carcinoma, sarcoma, melanoma, plasmacytoma, verrucous carcinoma, and oat cell (small cell) carcinoma; stomach cancers such as but not limited to, adenocarcinoma, fungating (polypoid), ulcerating, superficial spreading, diffusely spreading, malignant lymphoma, liposarcoma, fibrosarcoma, and carcinosarcoma; colon cancers; rectal cancers; liver cancers such as but not limited to hepatocellular carcinoma and hepatoblastoma; gallbladder cancers such as adenocarcinoma; cholangiocarcinomas such as but not limited to pappillary, nodular, and diffuse; lung cancers such as non-small cell lung cancer, squamous cell carcinoma (epidermoid carcinoma), adenocarcinoma, large-cell carcinoma and small-cell lung cancer; testicular cancers such as but not limited to germinal tumor, seminoma, anaplastic, classic (typical), spermatocytic, nonseminoma, embryonal carcinoma, teratoma carcinoma, choriocarcinoma (yolk-sac tumor), prostate cancers such as but not limited to, prostatic intraepithelial neoplasia, adenocarcinoma, leiomyosarcoma, and rhabdomyosarcoma; penal cancers; oral cancers such as but not limited to squamous cell carcinoma; basal cancers; salivary gland cancers such as but not limited to adenocarcinoma, mucoepidermoid carcinoma, and adenoidcystic carcinoma; pharynx cancers such as but not limited to squamous cell cancer, and verrucous; skin cancers such as but not limited to, basal cell carcinoma, squamous cell carcinoma and melanoma, superficial spreading melanoma, nodular melanoma, lentigo malignant melanoma, acral lentiginous melanoma; kidney cancers such as but not limited to renal cell carcinoma, adenocarcinoma, hypernephroma, fibrosarcoma, transitional cell cancer (renal pelvis and/or uterer); Wilms' tumor; bladder cancers such as but not limited to transitional cell carcinoma, squamous cell cancer, adenocarcinoma, carcinosarcoma. In addition, cancers include myxosarcoma, osteogenic sarcoma, endotheliosarcoma, lymphangioendotheliosarcoma, mesothelioma, synovioma, hemangioblastoma, epithelial carcinoma, cystadenocarcinoma, bronchogenic carcinoma, sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma and papillary adenocarcinomas (for a review of such disorders, see Fishman et al., 1985, Medicine, 2d Ed., J.B. Lippincott Co., Philadelphia and Murphy et al., 1997, Informed Decisions: The Complete Book of Cancer Diagnosis, Treatment, and Recovery, Viking Penguin, Penguin Books U.S.A., Inc., United States of America).

Accordingly, the methods and compositions of the invention are also useful in the treatment or prevention of a variety of cancers or other abnormal proliferative diseases, including (but not limited to) the following: carcinoma, including that of the bladder, breast, colon, kidney, liver, lung, ovary, pancreas, stomach, cervix, thyroid and skin; including squamous cell carcinoma; hematopoietic tumors of lymphoid lineage, including leukemia, acute lymphocytic leukemia, acute lymphoblastic leukemia, B-cell lymphoma, T-cell lymphoma, Burkitt's lymphoma; hematopoietic tumors of myeloid lineage, including acute and chronic myelogenous leukemias and promyelocytic leukemia; tumors of mesenchymal origin, including fibrosarcoma and rhabdomyoscarcoma; other tumors, including melanoma, seminoma, tetratocarcinoma, neuroblastoma and glioma; tumors of the central and peripheral nervous system, including astrocytoma, neuroblastoma, glioma, and schwannomas; tumors of mesenchymal origin, including fibrosarcoma, rhabdomyoscarama, and osteosarcoma; and other tumors, including melanoma, xeroderma pigmentosum, keratoactanthoma, seminoma, thyroid follicular cancer and teratocarcinoma. It is also contemplated that cancers caused by aberrations in apoptosis would also be treated by the methods and compositions of the invention. Such cancers may include but not be limited to follicular lymphomas, carcinomas with p53 mutations, hormone dependent tumors of the breast, prostate and ovary, and precancerous lesions such as familial adenomatous polyposis, and myelodysplastic syndromes. In specific embodiments, malignancy or dysproliferative changes (such as metaplasias and dysplasias), or hyperproliferative disorders, are treated or prevented in the skin, lung, colon, breast, prostate, bladder, kidney, pancreas, ovary, or uterus. In other specific embodiments, sarcoma, melanoma, or leukemia is treated or prevented.

In some embodiments, the cancer is malignant and overexpresses mesothelin. In other embodiments, the disorder to be treated is a pre-cancerous condition associated with cells that overexpress mesothelin.

The term “treatment” encompasses alleviation or prevention of at least one symptom or other aspect of a disorder, or reduction of disease severity, and the like. An antigen binding protein, in particular a human antibody according to the present invention, need not effect a complete cure, or eradicate every symptom or manifestation of a disease, to constitute a viable therapeutic agent. As is recognized in the pertinent field, drugs employed as therapeutic agents may reduce the severity of a given disease state, but need not abolish every manifestation of the disease to be regarded as useful therapeutic agents. Similarly, a prophylactically administered treatment need not be completely effective in preventing the onset of a condition in order to constitute a viable prophylactic agent. Simply reducing the impact of a disease (for example, by reducing the number or severity of its symptoms, or by increasing the effectiveness of another treatment, or by producing another beneficial effect), or reducing the likelihood that the disease will occur or worsen in a subject, is sufficient. One embodiment of the invention is directed to a method comprising administering to a patient an antigen binding protein such as a human antibody in an amount and for a time sufficient to induce a sustained improvement over baseline of an indicator that reflects the severity of the particular disorder.

As is understood in the pertinent field, pharmaceutical compositions comprising the antigen binding proteins of the invention are administered to a subject in a manner appropriate to the indication and the composition. In one embodiment, pharmaceutical compositions comprise the human antibodies of the present invention. Pharmaceutical compositions may be administered by any suitable technique, including but not limited to parenterally, topically, or by inhalation. If injected, the pharmaceutical composition can be administered, for example, via intra-articular, intravenous, intramuscular, intralesional, intraperitoneal or subcutaneous routes, by bolus injection, or continuous infusion. Delivery by inhalation includes, for example, nasal or oral inhalation, use of a nebulizer, inhalation of the antigen binding protein in aerosol form, and the like. Other alternatives include oral preparations including pills, syrups, or lozenges.

Advantageously, the antigen binding proteins of the invention, are administered in the form of a composition comprising one or more additional components such as a physiologically acceptable carrier, excipient or diluent. Optionally, the composition additionally comprises one or more physiologically active agents, for example, as described below. In various particular embodiments, the composition comprises one, two, three, four, five, or six physiologically active agents in addition to one or more antigen binding proteins (e.g, human antibodies) of the present invention.

In one embodiment, the pharmaceutical composition comprises a human antibody or antigen binding protein of the invention together with one or more substances selected from the group consisting of a buffer suitable for antibodies at a suitable pH, an antioxidant such as ascorbic acid, a low molecular weight polypeptide (such as those having fewer than 10 amino acids), a protein, an amino acid, a carbohydrate such as dextrin, a chelating agent such as EDTA, glutathione, a stabilizer, and an excipient. In accordance with appropriate industry standards, preservatives may also be added. The composition may be formulated as a lyophilizate using appropriate excipient solutions as diluents. Suitable components are nontoxic to recipients at the dosages and concentrations employed. Further examples of components that may be employed in pharmaceutical formulations are presented in Remington's Pharmaceutical Sciences, 16^(th) Ed. (1980) and 20^(th) Ed. (2000), Mack Publishing Company, Easton, Pa.

Kits for use by medical practitioners are provided including one or more antigen binding proteins of the invention and a label or other instructions for use in treating any of the conditions discussed herein. In one embodiment, the kit includes a sterile preparation of one or more human antibodies, which may be in the form of a composition as disclosed above, and may be in one or more vials.

Dosages and the frequency of administration may vary according to such factors as the route of administration, the particular antibodies employed, the nature and severity of the disease to be treated, whether the condition is acute or chronic, and the size and general condition of the subject. Appropriate dosages can be determined by procedures known in the pertinent art, e.g. in clinical trials that may involve dose escalation studies.

An antigen binding protein, in particular, the human antibodies, of the invention may be administered, for example, once or more than once, e.g., at regular intervals over a period of time. In particular embodiments, a human antibody or antigen binding protein is administered over a period of at least once a month or more, e.g., for one, two, or three months or even indefinitely. For treating chronic conditions, long-term treatment is generally most effective. However, for treating acute conditions, administration for shorter periods, e.g. from one to six weeks, may be sufficient. In general, the human antibody or antigen binding protein is administered until the patient manifests a medically relevant degree of improvement over baseline for the chosen indicator or indicators.

One example of therapeutic regimens provided herein comprise subcutaneous injection of an antigen binding protein such as a human antibody or antigen binding protein once a week, or once every two weeks, at an appropriate dosage, to treat a condition in which it is desired to target cells expressing mesothelin. Weekly or monthly administration of antigen binding protein would be continued until a desired result is achieved, e.g., the subject's symptoms subside. Treatment may resume as needed, or, alternatively, maintenance doses may be administered. Alternatively, various other routes of administration, such as intravenous, intraperitoneal, or intramuscular injection can be employed.

For the treatment of the disease, the appropriate dosage of the agent of the present invention depends on the type of disease to be treated, the severity and course of the disease, the responsiveness of the disease, whether the agent is administered for therapeutic or preventative purposes, previous therapy, patient's clinical history, and so on all at the discretion of the treating physician. The agent can be administered one time or over a series of treatments lasting from several days to several months, or until a cure is effected or a diminution of the disease state is achieved (e.g. reduction in tumor size). Optimal dosing schedules can be calculated from measurements of drug accumulation in the body of the patient and will vary depending on the relative potency of an individual antibody or antigen binding protein or agent. The administering physician can readily determine optimum dosages, dosing methodologies and repetition rates. In certain embodiments, dosage is from 0.01 μg to 100 mg per kg of body weight, and can be given once or more daily, weekly, monthly or yearly. In certain embodiments, the agent is given once every two weeks or once every three weeks. In certain embodiments, the dosage of the agent is from about 0.1 mg to about 20 mg per kg of body weight. The treating physician can estimate repetition rates for dosing based on measured residence times and concentrations of the drug in bodily fluids or tissues.

Combination Therapies

Particular embodiments of methods and compositions of the invention involve the use of an antigen binding protein such as an anti-mesothelin antibody or antigen binding proteins of the present invention and one or more cancer therapeutics, for example. In one embodiment, antigen binding proteins of the present invention are administered alone or in combination with other agents useful for treating the condition with which the patient is afflicted. Examples of such agents include both proteinaceous and non-proteinaceous drugs. When multiple therapeutics are co-administered, dosages may be adjusted accordingly, as is recognized in the pertinent art. “Co-administration” and combination therapy are not limited to simultaneous administration, but also include treatment regimens in which an antigen binding protein is administered at least once during a course of treatment that involves administering at least one other therapeutic agent to the patient.

In another aspect, the present invention provides a method of treating a subject with cancer or a hyperproliferative disorder associated with the expression or overexpression of mesothelin with a therapeutic antigen binding protein of the present invention, such as the fully human therapeutic antibodies described herein, together with one or more other treatments. In one embodiment, such a combination therapy achieves a synergistic effect. The antigen binding proteins may be in combination with one or more of the following treatments currently available. Nonlimiting examples of anti-cancer agents that can be used in the various embodiments of the invention, including pharmaceutical compositions and dosage forms and kits of the invention, include: acivicin; aclarubicin; acodazole hydrochloride; acronine; adozelesin; aldesleukin; altretamine; ambomycin; ametantrone acetate; aminoglutethimide; amsacrine; anastrozole; anthramycin; asparaginase; asperlin; azacitidine; azetepa; azotomycin; batimastat; benzodepa; bicalutamide; bisantrene hydrochloride; bisnafide dimesylate; bizelesin; bleomycin sulfate; brequinar sodium; bropirimine; busulfan; cactinomycin; calusterone; caracemide; carbetimer; carboplatin; carmustine; carubicin hydrochloride; carzelesin; cedefingol; chlorambucil; cirolemycin; cisplatin; cladribine; crisnatol mesylate; cyclophosphamide; cytarabine; dacarbazine; dactinomycin; daunorubicin hydrochloride; decitabine; dexormaplatin; dezaguanine; dezaguanine mesylate; diaziquone; docetaxel; doxorubicin; doxorubicin hydrochloride; droloxifene; droloxifene citrate; dromostanolone propionate; duazomycin; edatrexate; eflornithine hydrochloride; elsamitrucin; enloplatin; enpromate; epipropidine; epirubicin hydrochloride; erbulozole; esorubicin hydrochloride; estramustine; estramustine phosphate sodium; etanidazole; etoposide; etoposide phosphate; etoprine; fadrozole hydrochloride; fazarabine; fenretinide; floxuridine; fludarabine phosphate; fluorouracil; flurocitabine; fosquidone; fostriecin sodium; gemcitabine; gemcitabine hydrochloride; hydroxyurea; idarubicin hydrochloride; ifosfamide; ilmofosine; interleukin II (including recombinant interleukin II, or rIL2), interferon alpha-2a; interferon alpha-2b; interferon alpha-nl interferon alpha-n3; interferon beta-I a; interferon gamma-I b; iproplatin; irinotecan hydrochloride; lanreotide acetate; letrozole; leuprolide acetate; liarozole hydrochloride; lometrexol sodium; lomustine; losoxantrone hydrochloride; masoprocol; maytansine; mechlorethamine hydrochloride; megestrol acetate; melengestrol acetate; melphalan; menogaril; mercaptopurine; methotrexate; methotrexate sodium; metoprine; meturedepa; mitindomide; mitocarcin; mitocromin; mitogillin; mitomalcin; mitomycin; mitosper; mitotane; mitoxantrone hydrochloride; mycophenolic acid; nocodazole; nogalamycin; ormaplatin; oxisuran; paclitaxel; pegaspargase; peliomycin; pentamustine; peplomycin sulfate; perfosfamide; pipobroman; piposulfan; piroxantrone hydrochloride; plicamycin; plomestane; porfimer sodium; porfiromycin; prednimustine; procarbazine hydrochloride; puromycin; puromycin hydrochloride; pyrazofurin; riboprine; rogletimide; safingol; safingol hydrochloride; semustine; simtrazene; sparfosate sodium; sparsomycin; spirogermanium hydrochloride; spiromustine; spiroplatin; streptonigrin; streptozocin; sulofenur; talisomycin; tecogalan sodium; tegafur; teloxantrone hydrochloride; temoporfin; teniposide; teroxirone; testolactone; thiamiprine; thioguanine; thiotepa; tiazofurin; tirapazamine; toremifene citrate; trestolone acetate; triciribine phosphate; trimetrexate; trimetrexate glucuronate; triptorelin; tubulozole hydrochloride; uracil mustard; uredepa; vapreotide; verteporfin; vinblastine sulfate; vincristine sulfate; vindesine; vindesine sulfate; vinepidine sulfate; vinglycinate sulfate; vinleurosine sulfate; vinorelbine tartrate; vinrosidine sulfate; vinzolidine sulfate; vorozole; zeniplatin; zinostatin; zorubicin hydrochloride. Other examples of anti-cancer drugs include, but are not limited to: 20-epi-1,25 dihydroxyvitamin D3; 5-ethynyluracil; abiraterone; aclarubicin; acylfulvene; adecypenol; adozelesin; aldesleukin; ALL-TK antagonists; altretamine; ambamustine; amidox; amifostine; aminolevulinic acid; amrubicin; amsacrine; anagrelide; anastrozole; andrographolide; angiogenesis inhibitors; antagonist D; antagonist G; antarelix; anti-dorsalizing morphogenetic protein-1; antiandrogen, prostatic carcinoma; antiestrogen; antineoplaston; antisense oligonucleotides; aphidicolin glycinate; apoptosis gene modulators; apoptosis regulators; apurinic acid; ara-CDP-DL-PTBA; arginine deaminase; asulacrine; atamestane; atrimustine; axinastatin 1; axinastatin 2; axinastatin 3; azasetron; azatoxin; azatyrosine; baccatin III derivatives; balanol; batimastat; BCR/ABL antagonists; benzochlorins; benzoylstaurosporine; beta lactam derivatives; beta-alethine; betaclamycin B; betulinic acid; bFGF inhibitor; bicalutamide; bisantrene; bisaziridinylspermine; bisnafide; bistratene A; bizelesin; breflate; bropirimine; budotitane; buthionine sulfoximine; calcipotriol; calphostin C; camptothecin derivatives; canarypox IL-2; capecitabine; carboxamide-amino-triazole; carboxyamidotriazole; CaRest M3; CARN 700; cartilage derived inhibitor; carzelesin; casein kinase inhibitors (ICOS); castanospermine; cecropin B; cetrorelix; chlorins; chloroquinoxaline sulfonamide; cicaprost; cis-porphyrin; cladribine; clomifene analogues; clotrimazole; collismycin A; collismycin B; combretastatin A4; combretastatin analogue; conagenin; crambescidin 816; crisnatol; cryptophycin 8; cryptophycin A derivatives; curacin A; cyclopentanthraquinones; cycloplatam; cypemycin; cytarabine ocfosfate; cytolytic factor; cytostatin; dacliximab; decitabine; dehydrodidemnin B; deslorelin; dexamethasone; dexifosfamide; dexrazoxane; dexverapamil; diaziquone; didemnin B; didox; diethylnorspermine; dihydro-5-azacytidine; dihydrotaxol, 9-; dioxamycin; diphenyl spiromustine; docetaxel; docosanol; dolasetron; doxifluridine; droloxifene; dronabinol; duocarmycin SA; ebselen; ecomustine; edelfosine; edrecolomab; eflornithine; elemene; emitefur; epirubicin; epristeride; estramustine analogue; estrogen agonists; estrogen antagonists; etanidazole; etoposide phosphate; exemestane; fadrozole; fazarabine; fenretinide; filgrastim; finasteride; flavopiridol; flezelastine; fluasterone; fludarabine; fluorodaunorunicin hydrochloride; forfenimex; formestane; fostriecin; fotemustine; gadolinium texaphyrin; gallium nitrate; galocitabine; ganirelix; gelatinase inhibitors; gemcitabine; glutathione inhibitors; hepsulfam; heregulin; hexamethylene bisacetamide; hypericin; ibandronic acid; idarubicin; idoxifene; idramantone; ilmofosine; ilomastat; imidazoacridones; imiquimod; immunostimulant peptides; insulin-like growth factor-I receptor inhibitor; interferon agonists; interferons; interleukins; iobenguane; iododoxorubicin; ipomeanol, 4-; iroplact; irsogladine; isobengazole; isohomohalicondrin B; itasetron; jasplakinolide; kahalalide F; lamellarin-N triacetate; lanreotide; leinamycin; lenograstim; lentinan sulfate; leptolstatin; letrozole; leukemia inhibiting factor; leukocyte alpha interferon; leuprolide+estrogen+progesterone; leuprorelin; levamisole; liarozole; linear polyamine analogue; lipophilic disaccharide peptide; lipophilic platinum compounds; lissoclinamide 7; lobaplatin; lombricine; lometrexol; lonidamine; losoxantrone; HMG-CoA reductase inhibitor (such as but not limited to, Lovastatin, Pravastatin, Fluvastatin, Statin, Simvastatin, and Atorvastatin); loxoribine; lurtotecan; lutetium texaphyrin; lysofylline; lytic peptides; maitansine; mannostatin A; marimastat; masoprocol; maspin; matrilysin inhibitors; matrix metalloproteinase inhibitors; menogaril; merbarone; meterelin; methioninase; metoclopramide; MIF inhibitor; mifepristone; miltefosine; mirimostim; mismatched double stranded RNA; mitoguazone; mitolactol; mitomycin analogues; mitonafide; mitotoxin fibroblast growth factor-saporin; mitoxantrone; mofarotene; molgramostim; monoclonal antibody, human chorionic gonadotrophin; monophosphoryl lipid A+myobacterium cell wall sk; mopidamol; multiple drug resistance gene inhibitor; multiple tumor suppressor 1-based therapy; mustard anticancer agent; mycaperoxide B; mycobacterial cell wall extract; myriaporone; N-acetyldinaline; N-substituted benzamides; nafarelin; nagrestip; naloxone+pentazocine; napavin; naphterpin; nartograstim; nedaplatin; nemorubicin; neridronic acid; neutral endopeptidase; nilutamide; nisamycin; nitric oxide modulators; nitroxide antioxidant; nitrullyn; O6-benzylguanine; octreotide; okicenone; oligonucleotides; onapristone; ondansetron; ondansetron; oracin; oral cytokine inducer; ormaplatin; osaterone; oxaliplatin; oxaunomycin; paclitaxel; paclitaxel analogues; paclitaxel derivatives; palauamine; palmitoylrhizoxin; pamidronic acid; panaxytriol; panomifene; parabactin; pazelliptine; pegaspargase; peldesine; pentosan polysulfate sodium; pentostatin; pentrozole; perflubron; perfosfamide; perillyl alcohol; phenazinomycin; phenylacetate; phosphatase inhibitors; picibanil; pilocarpine hydrochloride; pirarubicin; piritrexim; placetin A; placetin B; plasminogen activator inhibitor; platinum complex; platinum compounds; platinum-triamine complex; porfimer sodium; porfiromycin; prednisone; propyl bis-acridone; prostaglandin J2; proteasome inhibitors; protein A-based immune modulator; protein kinase C inhibitor; protein kinase C inhibitors, microalgal; protein tyrosine phosphatase inhibitors; purine nucleoside phosphorylase inhibitors; purpurins; pyrazoloacridine; pyridoxylated hemoglobin polyoxyethylene conjugate; raf antagonists; raltitrexed; ramosetron; ras farnesyl protein transferase inhibitors; ras inhibitors; ras-GAP inhibitor; retelliptine demethylated; rhenium Re 186 etidronate; rhizoxin; ribozymes; RII retinamide; rogletimide; rohitukine; romurtide; roquinimex; rubiginone B1; ruboxyl; safingol; saintopin; SarCNU; sarcophytol A; sargramostim; Sdi 1 mimetics; semustine; senescence derived inhibitor 1; sense oligonucleotides; signal transduction inhibitors; signal transduction modulators; single chain antigen binding protein; sizofiran; sobuzoxane; sodium borocaptate; sodium phenylacetate; solverol; somatomedin binding protein; sonermin; sparfosic acid; spicamycin D; spiromustine; splenopentin; spongistatin 1; squalamine; stem cell inhibitor; stem-cell division inhibitors; stipiamide; stromelysin inhibitors; sulfinosine; superactive vasoactive intestinal peptide antagonist; suradista; suramin; swainsonine; synthetic glycosaminoglycans; tallimustine; tamoxifen methiodide; tauromustine; tazarotene; tecogalan sodium; tegafur; tellurapyrylium; telomerase inhibitors; temoporfin; temozolomide; teniposide; tetrachlorodecaoxide; tetrazomine; thaliblastine; thiocoraline; thrombopoietin; thrombopoietin mimetic; thymalfasin; thymopoietin receptor agonist; thymotrinan; thyroid stimulating hormone; tin ethyl etiopurpurin; tirapazamine; titanocene bichloride; topsentin; toremifene; totipotent stem cell factor; translation inhibitors; tretinoin; triacetyluridine; triciribine; trimetrexate; triptorelin; tropisetron; turosteride; tyrosine kinase inhibitors; tyrphostins; UBC inhibitors; ubenimex; urogenital sinus-derived growth inhibitory factor; urokinase receptor antagonists; vapreotide; variolin B; vector system, erythrocyte gene therapy; velaresol; veramine; verdins; verteporfin; vinorelbine; vinxaltine; Vitaxin®; vorozole; zanoterone; zeniplatin; zilascorb; and zinostatin stimalamer. Additional anti-cancer drugs are 5-fluorouracil and leucovorin. These two agents are particularly useful when used in methods employing thalidomide and a topoisomerase inhibitor. In a specific embodiment, the anti-mesothelin antibodies of the present invention are used in combination with gemcitabine.

Diagnostic Uses

In one aspect, anti-mesothelin antibodies of the invention are useful for detecting the presence of mesothelin in a biological sample. The term “detecting” as used herein encompasses quantitative or qualitative detection. In certain embodiments, a biological sample comprises a cell or tissue. In certain embodiments, such tissues include normal and/or cancerous tissues that express mesothelin at higher levels relative to other tissues.

In one aspect, the invention provides a method of detecting the presence of mesothelin in a biological sample. In certain embodiments, the method comprises contacting the biological sample with an anti-mesothelin antibody or antigen binding proteins under conditions permissive for binding of the anti-mesothelin antibody or antigen binding protein to mesothelin, and detecting whether a complex is formed between the anti-mesothelin antibody or antigen binding protein and mesothelin.

In one aspect, the invention provides a method of diagnosing a disorder associated with increased expression of mesothelin. In certain embodiments, the method comprises contacting a test cell with an anti-mesothelin antibody; determining the level of expression (either quantitatively or qualitatively) of mesothelin by the test cell by detecting binding of the anti-mesothelin antibody to mesothelin; and comparing the level of expression of mesothelin by the test cell with the level of expression of mesothelin by a control cell (e.g., a normal cell of the same tissue origin as the test cell or a cell that expresses mesothelin at levels comparable to such a normal cell), wherein a higher level of expression of mesothelin by the test cell as compared to the control cell indicates the presence of a disorder associated with increased expression of mesothelin. In certain embodiments, the test cell is obtained from an individual suspected of having a disorder associated with increased expression of mesothelin. In certain embodiments, the disorder is a cell proliferative disorder, such as a cancer or a tumor.

In certain embodiments, a method of diagnosis or detection, such as those described above, comprises detecting binding of an anti-mesothelin antibody to mesothelin expressed on the surface of a cell or in a membrane preparation obtained from a cell expressing mesothelin on its surface. In certain embodiments, the method comprises contacting a cell with an anti-mesothelin antibody under conditions permissive for binding of the anti-mesothelin antibody to mesothelin, and detecting whether a complex is formed between the anti-mesothelin antibody and mesothelin on the cell surface. An exemplary assay for detecting binding of an anti-mesothelin antibody to mesothelin expressed mesothelin on the surface of a cell is a “FACS” assay.

Certain other methods can be used to detect binding of anti-mesothelin antibodies to mesothelin. Such methods include, but are not limited to, antigen-binding assays that are well known in the art, such as western blots, radioimmunoassays, ELISA (enzyme linked immunosorbent assay), “sandwich” immunoassays, immunoprecipitation assays, fluorescent immunoassays, protein A immunoassays, and immunohistochemistry (IHC).

In certain embodiments, anti-mesothelin antibodies are labeled. Labels include, but are not limited to, labels or moieties that are detected directly (such as fluorescent, chromophoric, electron-dense, chemiluminescent, and radioactive labels), as well as moieties, such as enzymes or ligands, that are detected indirectly, e.g., through an enzymatic reaction or molecular interaction. Exemplary labels include, but are not limited to, the radioisotopes ³²P, ¹⁴C, ¹²⁵I, ³H, and ¹³¹I, fluorophores such as rare earth chelates or fluorescein and its derivatives, rhodamine and its derivatives, dansyl, umbelliferone, luceriferases, e.g., firefly luciferase and bacterial luciferase (U.S. Pat. No. 4,737,456), luciferin, 2,3-dihydrophthalazinediones, horseradish peroxidase (HRP), alkaline phosphatase, beta-galactosidase, glucoamylase, lysozyme, saccharide oxidases, e.g., glucose oxidase, galactose oxidase, and glucose-6-phosphate dehydrogenase, heterocyclic oxidases such as uricase and xanthine oxidase, coupled with an enzyme that employs hydrogen peroxide to oxidize a dye precursor such as HRP, lactoperoxidase, or microperoxidase, biotin/avidin, spin labels, bacteriophage labels, stable free radicals, and the like.

In certain embodiments, anti-mesothelin antibodies are immobilized on an insoluble matrix Immobilization entails separating the anti-mesothelin antibody or antigen binding protein from any mesothelin that remains free in solution. This conventionally is accomplished by either insolubilizing the anti-mesothelin antibody or antigen binding protein before the assay procedure, as by adsorption to a water-insoluble matrix or surface (Bennich et al., U.S. Pat. No. 3,720,760), or by covalent coupling (for example, using glutaraldehyde cross-linking), or by insolubilizing the anti-mesothelin antibody or antigen binding protein after formation of a complex between the anti-mesothelin antibody or antigen binding protein and mesothelin, e.g., by immunoprecipitation.

The invention having been described, the following examples are offered by way of illustration, and not limitation.

EXAMPLES Example 1—Generation of Anti-Mesothelin Antibodies Immunization

Fully human antibodies to human MSLN were generated by immunizing XenoMouse™ transgenic mice (Mendez et al., 1997; Kellerman and Green, 2002). Mice were immunized using routine methods. The full length mesothelin cDNA was cloned into an expression vector in frame with His and V5 antigen tags. The entire protein was expressed, but the cells subsequently cleaved the 30 kDa MPF fragment. The protein sequence comprising a.a. 1-293 of mesothelin, representing the membrane attached 40 kDa fragment, was injected into the mice.

The initial immunization was with 10 μg antigen admixed 1:1 v/v with TiterMax Gold. Subsequent boosts were made with 5 or 10 μg antigen admixed 1:1 v/v with 100 μg alum gel in pyrogen-free D-PBS and sometimes with 50% TiterMax Gold, followed by three injections with 10 μg antigen admixed 1:1 v/v with 10 μg mesothelin antigen in alum gel, and then a final boost of 10 μg antigen in PBS. In particular, each mouse was immunized in the footpad by subcutaneous injection. The animals were immunized on days 0, 4, 7, 10, 14, 17, 21, 32, and 45. The animals were bled on days 13 and 20 to obtain sera for harvest selection.

Anti-mesothelin antibody titers were determined by indirect ELISA. The titer value is the reciprocal of the greatest dilution of sera with an OD reading two-fold that of background. Briefly, mesothelin (84mer; 1 μg/mL) was coated onto Costar Labcoat Universal Binding Polystyrene 96 well plates overnight at four degrees. The solution containing unbound mesothelin was removed and the plates were treated with UV light (365 nm) for 4 minutes (4000 microjoules). The plates were washed five times with dH2O. Xenomouse™ mice sera from the mesothelin immunized animals, or naïve Xenomouse™ animals, were titrated in 2% milk/PBS at 1:2 dilutions in duplicate from a 1:100 initial dilution. The last well was left blank. The plates were washed five times with dH2O. A goat anti-human IgG Fc-specific HRP-conjugated antibody was added at a final concentration of 1 μg/mL for 1 hour at room temperature. The plates were washed five times with dH2O. The plates were developed with the addition of TMB for 30 minutes and the ELISA was stopped by the addition of 1 M phosphoric acid. The specific titer of individual Xenomouse™ animals was determined from the optical density at 450 nm. Lymph nodes from all immunized Xenomouse™ animals were harvested for fusion.

Immunized mice were sacrificed by carbon dioxide asphyxiation, and the lymph nodes harvested and pooled from each cohort. The lymphoid cells were dissociated by grinding in DMEM to release the cells from the tissues and the cells were suspended in DMEM. The cells were counted, and 0.9 ml DMEM per 100 million lymphocytes added to the cell pellet to resuspend the cells gently but completely. Using 100 μl of CD90+ magnetic beads per 100 million cells, the cells were labeled by incubating the cells with the magnetic beads at 40° C. for 15 minutes. The magnetically labeled cell suspension containing up to 108 positive cells (or up to 2×10⁹ total cells) was loaded onto a LS+ column and the column washed with DMEM. The total effluent was collected as the CD90-negative fraction (most of these cells are B cells).

P3 myeloma cells and B cell-enriched lymph node cells were combined in a ratio of 1:1 (myeloma:lymph nodes) into a 50 ml conical tube in DMEM. The combined cells were centrifuged at 800×g (2000 rpm) for 5-7 min. and the supernatant immediately removed from the resulting pellet. Two to four ml of Pronase solution (CalBiochem, Cat. #53702; 0.5 mg/ml in PBS) was added to the cells to resuspend the cell pellet gently. The enzyme treatment was allowed to proceed for no more than two minutes and the reaction stopped by the addition of 3-5 ml of FBS. Enough ECF solution was added to bring the total volume to 40 ml and the mixture was centrifuged at 800×g (2000 rpm) for 5-7 min. The supernatant was removed and the cell pellet gently resuspended with a small volume of ECF solution, followed by enough ECF solution to make a total volume of 40 ml. The cells were mixed well and counted, then centrifuged at 800×g (2000 rpm) for 5-7 min. The supernatant was removed and the cells resuspended in a small volume of ECF solution. Enough additional ECF solution was added to adjust the concentration to 2×10⁶ cells/ml.

The cells were then placed in an Electro-Cell-Fusion (ECF) generator (Model ECM2001, Genetronic, Inc., San Diego, Calif.) and fused according to the manufacturer's instructions. After ECF, the cell suspensions were carefully removed from the fusion chamber under sterile conditions and transferred into a sterile tube containing the same volume of Hybridoma Medium in DMEM. The cells were incubated for 15-30 minutes at 37° C., then centrifuged at 400×g (1000 rpm) for five minutes. The cells were gently resuspended in a small volume of ½ HA medium (1 bottle of 50× HA from Sigma, Cat. #A9666 and 1 liter of Hybridoma Medium) and the volume adjusted appropriately with more ½ HA medium (based on 5×10⁶B cells per 96-well plate and 200 μl per well). The cells were mixed well and pipetted into 96-well plates and allowed to grow. On day 7 or 10, one-half the medium was removed, and the cells re-fed with ½ HA medium.

Screening Antibodies

1. Selection of Candidate Antibodies for ELISA.

After 14 days of culture, hybridoma supernatants were screened for mesothelin-specific monoclonal antibodies. The ELISA plates (Fisher, Cat. No. 12 565 136) were coated with 50 μl/well of mesothelin (2 μg/ml) in Coating Buffer (0.1 M Carbonate Buffer, pH 9.6, NaHCO₃8.4 g/L), then incubated at 4° C. overnight. After incubation, the plates were washed with Washing Buffer (0.05% Tween 20 in PBS) 3 times. 200 μl/well Blocking Buffer (0.5% BSA, 0.1% Tween 20, 0.01% Thimerosal in 1×PBS) were added and the plates incubated at room temperature for 1 hour. After incubation, the plates were washed with Washing Buffer three times. Fifty (50) μl/well of hybridoma supernatants, and positive and negative controls were added and the plates incubated at room temperature for 2 hours. The positive control used throughout was XMG2 mesothelin Group 1, fp N160-7 and the negative control was XMG2 KLH Group 1, fp L627-6. After incubation, the plates were washed three times with Washing Buffer. One hundred (100) μl/well of detection antibody goat anti-hulgGfc-HRP (Caltag, Cat. #H10507), [and goat anti-hlgK-HRP(Southern Biotechnology, Cat. #2060-05) and goat anti-hIg (Southern Biotechnology, Cat. #2070-05) in secondary screening] were added and the plates incubated at room temperature for 1 hour. In the secondary screen, three sets of samples (positives in first screening) were screened, one set for hIgG detection, one set for hKappa detection and one set for hLambda detection. After incubation, the plates were washed three times with Washing Buffer. One hundred (100) μl/well of TMB (BioFX Lab. Cat. #TMSK-0100-01) were added and the plates allowed to develop for about 10 minutes (until negative control wells barely started to show color), then 50 μl/well stop solution (TMB Stop Solution (BioFX Lab. Cat. #STPR-0100-01) were added and the plates read on an ELISA plate reader at wavelength 450 nm.

2. FACS Analysis

To ascertain that the antibodies recognizing soluble mesothelin protein also recognized the antigen when bound to the cell surface, FACS analysis was performed on cells that express mesothelin, OvCar 8, and cells that do not express the antigen, 786-0.

Example 2—Binding Affinity of Anti-Mesothelin Antibodies

Binding affinity of the anti-MSLN antibodies of the invention was tested using assays well known in the art (Biacore® and Kinexa®) using general procedures outlined by the manufacturers. The data is summarized in FIG. 4.

The following describes binding activity as assessed by surface plasmon resonance using a BIAcore® biosensor device. Briefly, anti-human Fc (or anti-murine Fc) is covalently coupled to biosensor chips (i.e., a CMS chip) using a standard amine coupling procedure and reagents according to the manufacturer's instructions. Test antibody or a control antibody is injected over the immobilized anti-Fc, and varying amounts of MSLN (e.g., human, murine, rat, or cyno) are independently passed over an irrelevant antibody-coupled chip (negative control) as well as an anti-MSLN-coated chip using running buffer (e.g. 0.005% P20 surfactant). Regeneration of the chip may be accomplished with one 10-microliter pulse of 100 mM phosphoric acid at 10 microliters/minute. All binding is performed in HBS (10 mM HEPES, 0.15 M NaCl, 3.4 mM EDTA, 0.02% NaN3, 0.005% surfactant P20, pH 7.4) or equivalent. Binding curves were compared qualitatively for binding signal intensity, as well as for dissociation rates. Antibody binding kinetic parameters (dissociation rate constant “kd”) were determined, e.g., by using software provided by the manufacturer (e.g., BIA evaluation 3.0) that allows for global fitting calculations. The lower the dissociation equilibrium constants (expressed in pM), the greater the affinity of the antibody for MSLN.

Example 3—Mesothelin Species Cross-Reactivity of Anti-Mesothelin Antibodies

Reactivity of the antibodies of the invention against several species of mesothelin (cyno, rat, mouse) was tested using assays well known in the art. The data is summarized in FIG. 4.

FACS binding assays were performed to evaluate the binding of the anti-Mesothlelin antibodies to murine, rat and cynomologous monkey mesothelin orthologues, using recombinant forms of the various receptors transiently expressed on 293T cells. FACs assays were performed by incubating hybridoma supernatants with 10,000 to 25,000 cells in PBS/2% Fetal bovine serum/2 mM Calcium Chloride at 4° C. for one hour followed by two washes with PBS/2% Fetal bovine serum/2 mM Calcium Chloride. Cells were then treated with florochrome-labeled secondary antibodies at 4° C. followed by one wash. The cells were resuspended in 50 μl of PBS/2% FBS and antibody binding was analyzed using a FACSCalibur™ instrument.

Example 4—ELISA Cross-Competition and Binning of Anti-Mesothelin Antibodies

Cross-competition ELISA assays were performed to evaluate different “bins” of antibodies. The assays utilized techniques well known in the art. The data is summarized in FIGS. 5 and 6 and indicate that several antibodies bind to a MSLN epitope distinct from MORAb-009; and that Ab237 does not interfere with CA-125 binding while MORAb-009 does.

Certain antibodies, described herein were binned generally in accordance with the protocol described in U.S. Patent Application Publication No. 20030157730. Mouse anti-hIgG conjugated beads are prepared for coupling to primary antibody. The volume of supernatant needed is calculated using the following formula: (n+10)×50 μL (where n=total number of samples on plate). Where the concentration is known, 0.5 μg/mL is used. Bead stock is gently vortexed, then diluted in supernatant to a concentration of 2500 of each bead per well or 0.5×105/mL and incubated on a shaker in the dark at RT overnight, or 2 hours if at a known concentration of 0.5 μg/mL. Following aspiration, 50 μL of each bead is added to each well of filter plate, then washed once by adding 100 μL/well wash buffer and aspirating. Antigen and controls are added to filter plate 50 μL/well then covered and allowed to incubate in the dark for 1 hour on shaker. Following a wash step, a secondary unknown antibody is added at 50 μL using the same dilution (or concentration if known) as is used for the primary antibody. The plates are then incubated in the dark for 2 hours at RT on shaker followed by a wash step. Next, 50 μL/well biotinylated mouse anti-hlgG diluted 1:500 is added and allowed to incubate in the dark for one hour on shaker at RT. Following a wash step, 80 μL/well Streptavidin-PE is added at 1:1000 and allowed to incubate in the dark for 15 minutes on shaker at RT. Following a wash step, each well is resuspended in 80 μL blocking buffer and read using Luminex. Results show that the monoclonal antibodies belong to distinct bins. Competitive binding by antibodies from different bins supports antibody specificity for similar or adjacent epitopes. Non competitive binding supports antibody specificity for unique epitopes. Data is summarized in FIG. 5.

Functional Antibody Cross-Competition

In this antibody binning type set of experiments anti MSLN antibodies were tested for their ability to detect recombinant soluble human MSLN in a solid phase binding assay in which one antibody was used to capture soluble human MSLN in solution and the other antibody was employed to detect bound human MSLN. The ability of the antibodies to detect MSLN in this format indicated that they bound to distinct portions of MSLN (different non-overlapping epitopes) while the inability of a particular antibody pair to detect MSLN showed that they bound so a similar epitope or overlapping epitopes.

Capture antibodies (or CA125) listed across the top of the table were immobilized on Nalge Nunc Maxisorb 96-well clear Elisa plates in PBS at a concentration of 4 μg/ml overnight at 2-8 C. After washing in PBS-Tween 20 0.05% (PBS-T) 3 times, recombinant soluble MSLN was added in binding medium (PBS, 1% BSA, 10% NGS) to the starting well for titration 100 ng/ml in 100 μl. The soluble MSLN was then tritrated 8-12 well using a two-fold dilution and allowed to incubate with the capture antibody for 1 hour at 25° C. (room temperature). Unbound MSLN was removed by washing wells 3 times employing PBS. The various detection antibodies (listed in the left hand column of the table) were then added to the wells at a concentration of 1 μg/ml and the wells allowed to incubate at room temperature for 1 hour. To measure binding of bound detection antibodies-mouse anti human MSLN antibodies (MN, MB, OV569, 4H3), the wells were washed 3 times with PBS and then gt anti mouse IgG-HRP(Southern Biotech) was added to the wells for 30 minutes at room temperature. The wells were then washed again 3 times with PBS and the HRP-signal developed by adding 100 u of TMB substrate (K&P). The plate development was stopped by adding 1N sulfuric acid and reading the plate on a dual wave-length optical plate reader (450 nm-572 nm). In the case where the detection antibody was fully human(237, 158, 151) the antibody was added in along with MN or MB and detection of MN or MB was measured.

The results are summarized in FIG. 6. The results are reported as (+)-detection of soluble MSLN is not altered (≤2 fold reduction MSLN binding signal) in presence of competitor or EC50 for binding/detection is ≤1 ng/ml with the binding pair being assessed. Results reported as (−) indicates that soluble MSLN is not detected and that significant cross-competition for binding is observed.

Example 5—ADCC Activity of Anti-Mesothelin Antibodies

Throughout the specification, and in particular the examples, the terms “2×” and “3×” in reference to the anti-MSLN antibodies are used. These terms refer to substitutions in the Fc region that result in enhanced ADCC through increased binding affinity to the Fc receptor. The “2×” molecule has the following substitutions: S239D/I332E and the “3×” molecule has the following mutations: S239D/I332E/A330L.

1. Objectives

Determine the ability of Fc engineered fully human anti-MSLN antibodies to mediate ADCC as compared to the same unmodified, parental fully human anti-MSLN antibody.

2. Materials and Methods

2.1 Materials

Effectors: normal in-house donors were leukophoresed, and NK cells isolated from the leukopack by the Cell Purification Group using the Milteni AutoMacs Pro negative selection system. NK cells were held overnight at 4° C. on a rocker, then washed, counted and resuspended at 4×10⁶ cells/mL in complete RPMI for use in the ADCC assay.

Targets: Tumor cell targets were selected based on MSLN expression. Targets were washed and counted. 6×10⁶ targets are resuspended in complete RPMI and labeled in a final concentration of 10 μM calcein (Sigma #C1359-00UL CALCEIN AM 4 MM IN ANHYDROUS DMSO) for 40 minutes at 37 degrees, 5% CO2. Cells were washed twice in PBS, resuspended in complete RPMI and incubated at 37 degrees, 5% CO2 for 2 hrs. After labeling, target cells are washed, recounted and resuspended at 0.2×106 cells/mL in complete RPMI for use in the ADCC assay

2.2 Methods

Assay was performed in a 96 well round bottom tissue culture plate (Corning 3799). Antibodies were titrated from 20 μg/mL to 0.0002 μg/mL by carrying 10 μL in 100 μL of complete RPMI containing 10% FCS (a 1:10 dilution). Calcein labeled targets were added, 50 μL to contain 10,000 cells. Target cells and various concentrations of antibody were incubated for 40 minutes at 4° C., then NK cell effectors added, 50 μLto contain 100,000 cells (10:1 E:T ratio). Cultures were incubated for 4 hrs at 37° C. then supernatants pulled and assayed for calcein release by measuring fluorescence at 485-535 nm on a Wallac Victor II 1420 Multilable HTS counter. 100% lysis values were determined by lysing six wells of labeled targets with Igepal 630 detergent (3 μL per well) and spontaneous lysis values determined by measuring the fluorescence in supernatants from targets alone.

2.3 Statistical Analysis

Percent (%) specific lysis was defined as (sample fluorescence)−(spontaneous lysis fluorescence)/(100% lysis−spontaneous lysis fluorescence). Spontaneous lysis was determined by wells containing only targets and 100% lysis was determined by wells where targets had been lysed with IGEPAL CA 630 detergent. Raw data was entered in an Excel spreadsheet with embedded formulae to calculate % specific lysis and resultant values transferred to graphic program (GraphPad Prism) where the data was transformed in a curve fit graph Subsequent analyses (linear regression calculations) were done in GraphPad to generate EC50 values.

3. Results and Discussion

Effector NK cells in wells incubated with control hIgG1 antibody were unable to mediate killing of the calcein-labeled target cells while effectors in wells with certain fully human anti-MSLN antibodies were, as measured by specific Lytic activity (% specific lysis) able to mediate antibody dependent cellular cytotoxicity.

4. Conclusions

Both ADCC enhanced anti-MSLN and WT anti-MSLN antibodies were able to induce NK mediated killing of target tumor cells expressing MSLN. ADCC enhanced anti-MSLN antibodies mediate a significantly higher level of killing than the parent unmodified anti-MSLN antibodies.

Example 6—CDC Activity of Anti-Mesothelin Antibodies

1. Study Title: Anti-MSLN Antibodies Mediate Complement Dependent Cytotoxicity of Mesothelin Expressing Tumor Cells

2. List of Abbreviations and Definition of Terms

Abbreviation or Term Definition/Explanation FBS Fetal Bovine Serum CDC Complement Dependent Cytotoxicity (assay) CO2 Carbon Dioxide mL milliliter μL microliter n number SEM Standard error of the mean ° C. Degrees Celsius PI Propidium Iodide Ab Antibody IgG1 immunoglobulin class G1 HuIgG1 Human immunoglobulin class G1 237 WT Hu-anti-huMesothelin-2.37-IgG1, WT 237 3x Hu-anti-huMesothelin-237-IgG1, 3x 237 low fucose Hu-anti-huMesothelin-237-IgG1, clone 6F11 cBU69 WT Chimeric anti-human CD27L IgG1, WT cBU69 3x Chimeric anti-human CD27L IgG1, 3x

3. Objectives

The objective was to determine the ability of Fc-enhanced anti-human mesothelin 237 3× or 237 low fucose to mediate CDC as compared to the wild type anti-Mesothelin antibody 237 WT.

4. Materials and Methods

4.1 Materials

4.1.1 Test Materials

Antibody Drug Conjugates Source Formulation Human IgG₁ Kappa from Sigma, St. 20 nM tris buffered saline, human plasma Louis, MO pH 8.0. 237 WT Amgen Inc., 20 nM tris buffered saline, Seattle, WA pH 8.0. 237 3x Amgen Inc., Seattle, WA 237 low fucose Amgen Inc., Seattle, WA cBU69 WT Amgen Inc., Seattle, WA cBU69 3x Amgen Inc., Seattle, WA

4.1.2 Reagents

-   -   Target cells: Ovcar 8, Ovarian Carcinoma cells express         Mesothelin (65,000 MSLN/site) and CD27L. Growth medium contained         1 L of DMEM+L-glutamine+10% FBS+10 ml MEM non-essential Amino         Acids+10 ml HEPES+1 ml beta-mer captoethanol+5 ml Pen/strep+10         ml sodium pyruvate (=cDMEM)     -   Baby rabbit complement (Rt C′) (Cederlane, Burlington, Ontario,         Canada. Catalog #CL-3441-S. Lot #75540805.)     -   Heat inactivated (HI) complement was generated by incubating         complement at 56° C. in a water bath for 30 minutes and then         returning immediately to 4° C. The heat inactivated complement         was used within 1 hr of heat inactivation.     -   Assay medium: DMEM (basal medium) with 1% heat inactivated FBS.     -   Propidium iodide (PI), (Roche Diagnostics Corporation,         Indianapolis, Ind. Catalog #11348639001, lot #93352020).     -   Hoechst 33342, (Molecular Probes, Inc. Eugene, Oreg. Catalog         #H21492. Lot #24982W).

4.2 Methods

4.2.1 Preparation of Tumor Cells

Ovcar 8 cells were washed once with assay medium (DMEM plus 1% FBS) and resuspended in assay medium. Cells were seeded in a 96-well tissue culture plate at 100 μL per well with the cell density at 0.5×10⁴ cells per well. Cells were incubated at 37° C., 5% CO2 overnight.

4.2.2 Treatment of Cells with Complement and Control Antibody

Two times concentrated complement was prepared in assay medium as outlined in the table below. Medium in cell in 96-well plate was removed with plate washer. Then 2× rabbit complement was added to cells in plates at 50 μL per well.

Table for preparation of 2× concentrated rabbit complements in assay medium

Complement Assay Medium Total volume 2x complements (ml) (ml) (ml) 20% HI rabbit C′ 0.5 2 2.5 (inactive) 20% no HI rabbit C′ 1.5 6 7.5 (active)

Two times concentrated antibodies were added to cells at 50 μL per well as shown in the Experimental Design below to get a final concentration at 10 μg/mL. The total volume in each well at the start of culture was 100 μL. Cells were continuously incubated at 37° C., 5% CO2 for five hours.

Experimental Design: plate map for a 96-well plate. Antibodies were in duplicate wells for each sample with a total volume at 100 μl/well.

Note: Data obtained from NB 105783. Rt C′ is referred to as baby rabbit complement; Inactive C′ is referred to as heat inactivated complement.

4.2.3 Measurement of Cytotoxicity with ArrayScan Plate Reader

-   -   After 5-hour incubation, 150 μL of warm 2% FBS in PBS were added         to each well. The plates were centrifuged at 1000 rpm for 5 min.         The medium were discarded with plate washer where its needles         were set to a height that allowed 50 μL of medium left in each         well.     -   The cocktail of Hoechst 33342 and propidium iodide (PI) which         was prepared at 1:1000 dilution in PBS solution containing 2%         FBS was added into cells at 100 μL per well.     -   Samples were analyzed on an ArrayScan VTI HCS reader (version 6,         Cellomics, Thermo Fisher Scientific, Pittsburgh, Pa.) with         BioApplication “Target Activation” employing a 20× objective.         The filter setting was indicated in table below. At least 200         cells were counted in each well.

Channel Target Label Fluor Filter 1 Nucleic acid for Hoechst 33342 UV/460 nm DAPI all cells 2 Nucleic acid for Propidium iodide 488/>575 nm TRITC dead cells

4.3 Statistical Analysis

Statistical analysis was performed using Prism 4.01 (GraphPad, San Diego, Calif.). A plot shows % cytotoxicity vs. the log of Ab concentration in μg/mL. The % cytotoxicity in Y axis is represented with % selected objects from output feature of ArrayScan reader and expressed as the mean+/−standard error of the mean (SEM) for duplicate measurements (n=2) except control antibodies measured in single wells.

5. Supporting Data

5.1 Figures

All WT, 3× and Low Fucose of Mesothelin HuG1, Clone 237 did not show any complement-dependent cytotoxicity (CDC) mediated killing with 10% rabbit complement against Ovcar 8 after 5 h incubation.

Ovcar8 cells were exposed to doses of anti-Mesothelin WT or Fc-enhanced antibodies or its negative control, huG1 and positive controls cBu69 and cBU69 3× starting at 10 μg/mL (up panel). Then cells were treated with active or inactive (56° C., 30′) rabbit complement (Rt C′) at final concentration of 10% (up and low panel). After incubation at 37° C., 5% CO2 for 5 hrs, CDC mediated killing was measured from output feature of ArrayScan reader “% selected objects” to detect % of PI positive vs. Hoechst for % Cytotoxicity. Data are expressed as the mean and standard error of the mean (SEM) for duplicate measurements (n=2) except single wells for controls. The results of this study are summarized in FIGS. 7-9 and indicate that none of the anti-MSLN antibodies demonstrated CDC mediated cell killing.

Example 7—ADCP Activity of Anti-Mesothelin Antibodies

Anti-MSLN Antibodies Mediate Antibody Dependent Cellular Phagocytosis of Mesothelin Expressing Tumor Cells

1. List of Abbreviations and Definition of Terms

Abbreviation or Term Definition/Explanation FBS Fetal Bovine Serum RPMI Roswell Park Memorial Institute CO2 Carbon Dioxide mL milliliter μL microliter n number NA Not applicable SEM Standard error of the mean ° C. Degrees Celsius ATCC American Type Culture Collection RT Room temperature Ab Antibody IgG1 immunoglobulin class G1 HuIgG1 Human immunoglobulin class G1 ADCP Antibody Dependent Cellular Phagocytosis (assay) 237 WT Hu-anti-huMesothelin-2.37-HuIgG1, WT 237 3x Hu-anti-huMesothelin-237-HuIgG1, 3x 237 low fucose Hu-anti-huMesothelin-237-HuIgGl, clone 6F11 EC50 Half maximal effect concentration

2. Objectives

Determine the ability of anti-MSLN antibodies to mediate ADCP.

3. Materials and Methods

3.1 Materials

3.1.1 Test Materials

Antibody Drug Conjugates

237 WT

237 3×

237 low fucose

Human IgG1 Kappa from human plasma (Cat.#I5154 1 mg; Sigma, St. Louis, Mo.)

20 nM tris buffered saline, pH 8.0

3.1.2 Reagents

-   -   Target cells: Ovcar 8, Ovarian Carcinoma cells express         Mesothelin (65,000 MSLN/site) and CD27L. Growth medium contained         1 L of DMEM+L-glutamine+10% FBS+10 ml MEM non-essential Amino         Acids+10 ml HEPES+1 ml beta-mer captoethanol+5 ml Pen/strep+10         ml sodium pyruvate (=cDMEM)     -   Effectors: normal in-house donor #1193 was monocytes isolated         from the human peripheral blood by the Cell Purification Group         (Amgen Inc., Seattle, Wash.) using the Milteni AutoMacs Pro         negative selection system. Cells were held overnight at 4° C. on         a rocker, then washed, counted and resuspended in complete RPMI         for use in the ADCP assay.     -   PKH67 green fluorescent cell linker kit for general cell         labeling (Sigma-Aldrich Corporation, St. Louis, Mo. Catalog         #PKH67-GL, lot #076K0463).     -   CD11b-Biotin: mouse anti-human CD11b/Mac-1 monoclonal antibody,         clone ICRF44, IgG1, Kappa. (eBioscience, San Diego, Calif.         Catalog #13-0118-82, lot #E026682).     -   Streptavidin, Alexa 568 conjugate (Molecular Probes, Inc.         Eugene, Oreg. Catalog #S-11226. Lot #34757A).     -   Hu M-CSF: recombinant human M-CSF(R&D Systems, Minneapolis,         Minn. Catalog #216-MC-025, lot #MVND 16061).

3.2 Methods

Day 0: Differentiation of Human Macrophage Cells from Purified Monocytes

Monocytes were negative selected from human peripheral blood and stored in 4° C. cold room over night with medium RPMI 1640 containing 10% FBS. Then monocytes were seeded to a 48-well tissue culture plate at 200,000 cells per well with 200 μL of macrophage growth medium (RPMI 1640 containing 10% FBS and 40 ng/ml Hu M-CSF) and incubated at 37° C., 5% CO2 for 5-7 days to let monocytes differentiate to macrophages.

Day 6: Performance of ADCP Assay

1. Labeling target cells with PKH67 green dye at final concentrations of 2×10⁻⁶ M PKH67 dye

-   -   Tumor cells were collected and washed once with PBS by         centrifuging the cells (400′ g) for 5 minutes.     -   After centrifuging cells, the supernatant was carefully         aspirated, but leaving no more than 25 mL of supernatant.     -   Four μL of the PKH67 ethanolic dye solution at stock         concentration of 4×10⁻⁶ M was added to 1 ml of Diluent C from         kit in polypropylene tube and mixed well.     -   Cell pellets were re-suspended into 1 mL of Diluent C at a         density of 20×10⁶ in polypropylene tube.     -   Cells were rapidly transferred to dye work solution with gently         pipetting to insure complete dispersion.     -   The mixture was incubated at room temperature for 4 minutes with         mixing periodically.     -   Two mL of whole activated FBS was added into cells to stop the         staining and incubated at room temp for 1 minute to allow         binding of excess dye.     -   Forty mL of RPMI containing 10% FBS was added into cells and         washed once by centrifuging the cells (400′ g) for 10 minutes.     -   Cell pellets were suspended with 40 mL of medium again and         transferred to a new tube.     -   Cells were washed again three times with medium RPMI+10% FBS and         1× with macrophage growth medium (RPMI 1640 containing 10% FBS         and 40 ng/ml Hu M-CSF).     -   Cells were counted and suspended with macrophage growth medium         at 1×10⁶ cells per mL for T: E at 1:2 ratio.

2. Treatment of tumor cells with antibodies for antibody dependent cellular phagocytosis (ADCP)

-   -   Antibody dilutions were prepared in macrophage growth medium.         These dilutions were concentrated at four times higher than         final concentrations.     -   To preincubate PKH67 green labeled target cells with antibodies,         300 μl of 4× concentrated antibodies was mixed with 300 μl of         green labeled tumor cells and incubated at 4° C. for 30 minutes.     -   The mixture of green labeled tumor cells with anti-tumor         antibodies was added to macrophage cells in 48-well plate at 200         μl for each well as indicated in the Experiment Design table         below. The final volume is 0.4 ml per well. The ratio of target         cells to effect cells (macrophages) is 1:2.     -   Cells were incubated at 37° C., 5% CO2 for one hour.

Experimental design: plate map for 48-well plate. Duplicate for each treatment

3. Counterstaining macrophages with macrophage marker

-   -   Target cells and macrophages in 48-well plate were detached with         Trypsin-Versene mixture.     -   Cells were transferred into a 96-well block with 2.2-ml volume         per well and washed once with pre-warmed FASC wash solution by         spinning the blocks at 400′ g for 5 minutes and then discarding         supernatant.     -   Macrophages were stained with their marker, CD11 b-Biotin at         1:200 dilution in block solution with 100 μl per well for 10 min         on ice.     -   After washing cells once, macrophages were detected with         streptavidin Alexa 568 at 1:1000 dilutions for 10 minute on ice.     -   After washing cells 1× with PBS, cells were fixed with 4%         formaldehyde in PBS at room temperature for 20 minutes. Then         cells were washed 1× with dH2O.     -   Cell pellets were resuspended with water at 200 μl per well and         transferred to a 96-well plate at 100 μl per well. Plate can be         sealed and stored at 4° C. overnight if needed.

4. Quantitative measurement of phagocytosis activity on an ArrayScan VTI HCS reader (version 6, Cellomics Inc. Thermo Fisher Scientific, Pittsburgh, Pa.) with Target Activation BioApplication employing a 20× objective. The filter setting was indicated in table below. At least 200 cells were counted in each well.

Filter Setting for ADCP:

Channel Target Label Fluor 1 macrophages Ms-anti-Hu CD11b Biotinαstreptavidin red Alexa 568 2 Tumor cells PHK67 green

3.3 Statistical Analysis

Statistical analysis was performed using Prism 4.01 (GraphPad, San Diego, Calif.). A plot shows % tumor cell phagocytosis vs. the log of antibody concentration in ng/ml. The percentage of tumor cell phagocytosis is represented with percentage of tumor cells that were overlapped with macrophages vs. total macrophages in the selected fields and obtained from output feature of ArrayScan reader “% ObjectCounts”. The % values were expressed as the mean+/−standard error of the mean (SEM) for duplicate measurements (n=2). The EC50 was determined by using nonlinear regression analysis (Sigmoidal dose response curve fit). Data were normalized to the maximum and minimum signal and fit to a sigmoidal dose-response curve.

4. Supporting Data

4.1 Anti-MSLN Antibodies Induce Human Macrophages to Phagocytose Ovcar 8 Cells

Anti-MSLN antibodies mediate ADCP activity against Ovcar 8 cells. Phagocytosis images were captured using ArrayScan VTI plate reader at 20× magnification. Green dye labeled tumor cells were exposed to anti-MSLN antibodies (237 Low Fucose MSLN) or its negative control, HuG1. Then cells were mixed with human macrophages at a ratio of 2:1 (effectors: tumor). After incubation at 37° C., 5% CO2 for 1 hr, macrophages were detected with the marker CD11b-Biotin plus anti-streptavidin (αSA) Alexa 568 (red). FIG. 10 contains photographic images of these experimental results.

Fc-enhanced Anti-Mesothelin HuG1, Clone 237-3x and -Low Fucose Enhance Tumor Cell Phagocytosis Compared to 237 WT in Ovcar 8 After 1 h Incubation

Anti-MSLN antibodies mediate ADCP activity by human macrophages. Mesothelin expressing tumor cell line Ovcar 8 was exposed to 237 WT, or Fc enhanced Abs, 237 3× and 237 low fucose or its negative control, HuG1. Then cells were mixed with human macrophages at a ratio of 2:1 (effectors: tumor). After incubation at 37° C., 5% CO2 for 1 hr, macrophages were detected with the marker CD11b. The ADCP activity in Y axis was measured from output feature of ArrayScan VTI reader “% selected objects” to detect % of tumor cells were phagocytized into macrophages. Data are expressed as the mean and standard error of the mean (SEM) for duplicate measurements (n=2). FIG. 11 summarizes these results.

Example 8—Soluble MSLN Vs. Surface MSLN Binding

Experiments were run to determine binding affinity of the anti-MSLN antibody ab237 against native surface bound MSLN and soluble MSLN. It was determined that ab237 binds native surface bound MSLN with 30-fold higher selectivity as compared to soluble MSLN.

237 anti MSLN bind with greater affinity to native human MSLN expressed on the cell surface than recombinant soluble MSLN

ab237 Binding Affinity rHuMSLN sol.^(#) 97 pM K_(D) Hu MSLN native* 3.5 pM

Equilibrium binding of 237 antibody was assessed to native human MSLN expressing N87 tumor cells utilizing KinExA technology. The results of binding of 237 to native human MSLN are reported as the equilibrium binding constant or KD in pM. Binding of 237 to recombinant human soluble MSLN (rHuMSLN sol.) was assessed in solution by Biacore analysis. The 237 antibody was captured on the Biacroe sensor chip and the solution containing rHuMSLN sol was allowed to flow across the chip until binding equilibrium reached. Both the association and dissociation constants were measured and the results reported as the equilibrium binding constant or KD in pM. The results showed that the 237 mAb bound 30-fold better to native MSLN expressed on the cell surface than it did to soluble MSLN in solution.

Example 9—In Vivo Efficacy of Anti-Mesothelin Antibodies

In vivo experiments were performed to evaluate the efficacy of the anti-MSLN antibodies of the invention. The data from these experiments is summarized in FIGS. 15-17.

The ability of Fc-enhanced 237 anti MSLN to mediate anti tumor activity in vivo was assessed in the N87 gastric cancer xenograft model. Prior to implantation mice barcode chips were implanted into CB-17/SCID mice that would receive tumor implants. N87 gastric cancer cells (2×10∧6) in 100 μl were implanted subcutaneously in an equal volume of growth-factor reduced Matrigel (BD). Following implantation, the animals were either immediately treated with 237 mAb or with control mAb as indicated in FIG. 16 (left panel) or starting on the fourth day post tumor implantation FIG. 16 (right panel), FIG. 17 and FIG. 18. When initiation of treatment was delayed to day 4 post tumor implantation, the tumors were measured and the mice randomized into treatment groups of 10 so that the average tumor volume across the groups was similar prior to the start of treatment.

The control IgG1 antibody, 237 or MorAb-009 (FIG. 17) were administered twice per week i.p. for three weeks at the doses indicated in each figure. Where indicated, Gemcitabine was administered i.p. at the doses indicated on the FIG. 16 (left panel). 17 and 18 on day 4, 7 and 11 post tumor implant. Tumor volume was assessed twice weekly by taking perpendicular measurements, electronic using calipers and recordering the measure associated with the bar code read in an xls spreadsheet. Control treated N87 tumors typically reached>1000 mm ∧3 by day 28-30 so that is when the studies were designed to end for results presented in FIGS. 16 and 17. In the combination xenograft study (FIG. 18) where 237 was combined with gemcitabine the study was carried out to almost 55 days because the anti tumor effect was more pronounced and one of the outcomes of the experiment was to assess treatment durability. The results are reported as the average tumor volume+/−standard error of the mean over time. Statistical differences between groups was assessed using repeated measures ANOVA followed by post hoc analysis using Dunnett's for multiple comparisons (Graph Pad Prism, 5.0). When comparing the anti-tumor effect of one treatment group to another, a p-value of <0.05 was considered to be indicative a statistical difference between treatment groups.

Example 10—MSLN BiTE Binding

Binding of MSLN-BiTE to membrane-bound target expressed in cells was determined with an on-cell affinity assay. 3×10⁴ cells per well of a microtiter plate were incubated with MSLN-BiTE protein in a dose response for 16-22 h at 4° C. Cells were washed twice with flow buffer (PBS that contained 2% fetal calf serum and 0.01% sodium azide), and then resuspended in flow buffer and incubated with an anti-His Fab labeled with Alexa Fluor-647 for 50 minutes at 4° C. Cells were fixed after incubation to optimize detection of the fluorescent signal. Cells were then washed twice and resuspended in flow buffer that contained propidium iodide at 1 μg/ml. Cells were analyzed by flow cytometry for live cells that were positive for Alexa Fluor-647. EC₅₀ values were determined from the dose response curve of Alexa Fluor-647 positive cells.

FIG. 20 shows the results of binding of representative MSLN-BiTE proteins to human MSLN in NCI—N87 gastric cancer cells and to human CD3 in HPB-ALL cells. Solid lines in the graphs below indicate VH-VL orientation and dotted lines indicate the VL-VH orientation. FIG. 22 shows the results of binding of representative MSLN-BiTE proteins to human MSLN in OVCAR-8 ovarian cancer cells and to human or cyno MSLN in 293T cells that are transiently transfected with human MSLN or cyno MSLN.

Example 11—MSLN BiTE T-Cell Activation

OVCAR-8 cells were incubated at 40,000 cells per well with unstimulated pan-T cells (ALL CELLS) at a 10:1 effector to target cells ratio and BiTE proteins. The T cells are pre-labeled with 5 μM CSFE dye. MEC14-BiTE is directed against murine anti-Mecoprop and is a negative control for the assay (Osada et al., Br. J. Cancer 2010). Cetuximab-BiTE is a BiTE generated from the Cetuximab anti-EGFR antibody (Lutterbuese et al., PNAS 2010) that serves as a positive control for this assay due to expression of EGFR in OVCAR-8 cells. Both cytokine production and T cell activation were determined from this assay.

At 24 h, aliquots of supernatants were removed and assayed for the production of cytokines by multiplex ELISA assays (Meso Scale Discovery). Briefly, spots within wells of a microtiter dish are precoated with an antibody against the target cytokine of interest. Supernatants from the incubation of BiTE, tumor cells and T cells are added to the wells of the cytokine assay plate, and then binding of cytokines to the bound antibody is detected by a chemiluminescent detection reagent. The chemiluminescent signal is quantitated with a plate reader and the EC₅₀ values are calculated from the dose response curves. Cytokines produced by the reaction of BiTE with target-expressing tumor cells and T cells included: IL-6 (shown in FIGS. 23 and 25), TNF-α, IFN-γ, MCP-1, IL-1B, IL-2, IL-4, IL-10, IL-12 and IL-13. Results from the other cytokine assays are summarized in FIG. 23.

At 48 h, the remaining supernatants were assayed for T cell activation, by increase in CD25⁺ or CD69⁺ T cells. T cells were washed in flow buffer and then incubated with monoclonal antibodies to CD25, CD69 or an isotype control antibody for 30 minutes at room temperature. Cells were then washed twice with flow buffer and analyzed by flow cytometry for gain of CD25-positive or CD69-positive T cells. Dose response curves were obtained by graphing the number of CD25⁺ or CD69⁺ cells at each dose. The increase in CD25⁺ cells is shown in FIGS. 22 and 24. T cell proliferation was also assessed in the flow cytometry experiments by measuring the loss of CSFE signal, a marker for mitotic index (data not shown).

Example 12—MSLN-BiTE Cytotoxicity

Cytoxicity assays for the MSLN-BiTE molecules were performed generally as described above in Example 5, except that pan-T cells were used as effector cells. BiTE proteins were incubated with MSLN-expressing tumor cells OVCAR-8 at 2500 cells per well of a microtiter plate, and unstimulated pan-T cells (source: ALL CELLS) in a 10:1 effector to target cells ratio, for 48 h at 37° C., 5% CO2. Cells were then stained with 10 μM Hoechst 33342 to visualize the cell nuclei, and 2 μM propidium iodide to specifically label the nuclei of dead cells. After incubation with the DNA stains for 90 min at 37° C., 5% CO2, the microplate wells were scanned by high content imaging (ArrayScan) to capture images of the cells. Percent specific cytotoxicity was calculated using the formula: [1−live target cell count (+BiTE)/live target cell count (−BiTE)]×100. Results are summarized in FIGS. 25 and 26.

Example 13—In Vivo Efficacy of MSLN-BiTEs

Admixture Model:

Athymic nude female mice (Harlan) are implanted subcutaneously in the flank with a mixture of 5×10⁶NCI—N87 gastric cancer cells and 2.5×10⁶ human PBMCs (1:2 effector:target cell ratio). Mice are dosed with an intraperitoneal (ip) injection of MSLN-BiTE that contains the 2.37 scFv and the 8H9 CD3 (P73362) or vehicle control once a day for 10 days. Each dosing group contains 10 mice. Caliper measurement of tumor size is determined every 3-4 days until day 28 when the study is terminated. Body weights are maintained throughout the study. Results are summarized in FIG. 27.

BiTE Screen Model:

Athymic nude female mice (Harlan) are implanted subcutaneously with four xenograft model cell lines at different sites on the flank (see diagram in FIGS. 29 and 30). Each cancer cell line is labeled with luciferase and mixed 1:1 (5×10⁵ cells each) with human pan-T cells isolated from PBMCs. The BiTE screen model used here tests NCI—N87 cells (53,000 MSLN sites/cell), OVCAR-8 cells (65,000 MSLN sites/cell), SK—OV-3 cells (15,000 MSLN sites/cell) and A2780 cells (MSLN-negative). Baseline cell luciferase signal is measured by Xenogen imaging on Day 1. Mice are dosed intraperitoneally once a day for 11 days with MSLN-BiTE or vehicle, with 5 mice per dosing group. Cell luciferase signal is measured every 3 days (Day 1, 4, 7 and 11) to monitor tumor growth. Tumor growth inhibition is determined by fold change in the luciferase signal.

In one study, the effect of the MSLN-BiTE that contains the 2.37 scFv and the 8H9 CD3 (P73362) was tested. This study showed that the MSLN-BiTE is active in the BiTE screen model. Growth of cancer cell lines that express MSLN is inhibited, and growth of the MSLN-negative cell line A2780 was not affected. Results are summarized in FIG. 28.

In another study, in vivo activity of the MSLN-BiTE proteins 2.37HL-BiTE and 1.33HL-BiTE, which use the I2C CD3, were tested. Both MSLN-BiTE proteins were active in the BiTE screen, and inhibited tumor growth of the MSLN-expressing cell lines. Results are summarized in FIG. 29.

Blood plasma pharmacokinetics of the MSLN-BiTE showed increased levels of the BiTE present with higher dose, consistent with the dose-dependent effect on tumor growth (FIG. 30).

Each reference cited herein is hereby incorporated by reference in its entirety for all that it teaches and for all purposes.

The present invention is not to be limited in scope by the specific embodiments described herein, which are intended as single illustrations of individual aspects of the invention, and functionally equivalent methods and components are invention. Indeed, various modifications of the invention, in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims. 

What is claimed is:
 1. An isolated nucleic acid encoding an antibody, antigen binding protein, or fragment thereof, wherein the antibody, antigen binding protein, or fragment thereof comprises a mesothelin binding domain comprising three heavy chain CDRs and three light chain CDRs with sequences selected from the group consisting of: a) SEQ ID NOs: 45, 46, and 47 of the heavy chain and SEQ ID NOs: 9, 10, and 11 of the light chain; b) SEQ ID NOs: 48, 49, and 50 of the heavy chain and SEQ ID NOs: 12, 13, and 14 of the light chain; c) SEQ ID NOs: 51, 52, and 53 of the heavy chain and SEQ ID NOs: 15, 16, and 17 of the light chain; d) SEQ ID NOs: 51, 52, and 53 of the heavy chain and SEQ ID NOs: 18, 19, and 20 of the light chain; e) SEQ ID NOs: 54, 55, and 56 of the heavy chain and SEQ ID NOs: 21, 22, and 23 of the light chain; f) SEQ ID NOs: 57, 58, and 59 of the heavy chain and SEQ ID NOs: 24, 25, and 26 of the light chain; g) SEQ ID NOs: 60, 61, and 62 of the heavy chain and SEQ ID NOs: 27, 28, and 29 of the light chain; h) SEQ ID NOs: 63, 64, and 65 of the heavy chain and SEQ ID NOs: 30, 31, and 32 of the light chain; i) SEQ ID NOs: 63, 64, and 65 of the heavy chain and SEQ ID NOs: 33, 34, and 35 of the light chain; j) SEQ ID NOs: 63, 64, and 65 of the heavy chain and SEQ ID NOs: 36, 37, and 38 of the light chain, and k) any one of (a)-(j), wherein each of said CDRs are identical to or comprise 1, 2, or 3 amino acid residue substitutions relative to their specified sequence.
 2. A vector comprising the nucleic acid of claim
 1. 3. A host cell comprising the nucleic acid of claim
 1. 4. A host cell comprising the vector of claim
 2. 5. A method for producing an antibody, antigen binding protein, or fragment thereof comprising culturing the host cell of claim 3 under suitable conditions and recovering said antibody.
 6. A method for producing an antibody, antigen binding protein, or fragment thereof comprising culturing the host cell of claim 4 under suitable conditions and recovering said antibody.
 7. A method of inhibiting or reducing the growth of mesothelin expressing tumor cells in a subject, comprising administering to said subject a therapeutically effective dose of an antibody, antigen binding protein, or fragment thereof encoded by the nucleic acid of claim
 1. 